Celestron RASA 8 - A Comprehensive Review

[@brendanmanning1959]

I really appreciate the detail of your explanations. It has significantly helped me understand the basics to get into astrophotography. Thank you

[@peterraymond3653]

Thanks for a very informative vid. I've just bought a RASA 8 to go with my ZWO_asi 1600mm-pro OSC but am concerned the chip might be a bit small. I'm from the UK where condensation is a big problem and have taken note about your fantastic dew shield / diffraction spikes idea. Again thanks for an awesome, informative vid. Subscribed.

[@andrewlindenfeld6222]

Just used my rasa 8 last night on the Leo Triplet. Got 3.5 hrs of data and it looks fantastic. Can’t wait to process it!

[@AstroBlender]

Awesome! I just imaged this the other day. My latest Instagram image. I think it turned out okay. I’d like to get to darker skies and try again.

[@jasonrichuitti8587]

Hi,just wanted to say thanks! Your videos have helped me tremendously!I'm a rookie that is hooked like a junkie and the learning curve of this hobby is steep but because people like you putting out quality information allows newbies like me to lean and accomplish my astrophotography goals. Thank you again!!

[@AstroBlender]

Hi Jason, I’m so happy to hear this! Thanks for the great feedback and I’m glad you’re getting into it! Clear skies!

[@Lank871]

I really love the detail you show in your footage. Often videos are more of a talking head scene so you don't see the details of these scopes. This is absolutely excellent. Keep it up :)

[@Noncenx]

Your videos have been a lot of help as I've gotten more and more involved with this hobby. I've got one now for the RASA 8. I didn't intend to get one but the price was too good to pass up and now I'm working on getting it up and running. You're back focus video on the RASA was just what I needed. Now, I have a question now about guiding. Many people tell me I don't have to worry about guiding due to the shorter exposures but I notice you have a guide scope and camera on your RASA. Could you clarify this for me, if they're needed and if not, why do you have one. Thanks

[@AstroBlender]

It depends on how short I guess. Anything 30 seconds or longer, I always guide, as there are only benefits, no cons. It also allows me to dither my images, which for me is a must.

[@michaelk8642]

As usual, fantastic video. It was very informative with a lot of useful information. I have had my eye on a RASA for a few months now, and once dealers get stock back in, I may just pull the trigger and pick one up. Thanks a bunch!

[@AstroBlender]

I’m glad you found the information helpful! One day things may come back in stock! 😃

[@xee1429]

Hey Cody, happy new year love your videos. Quick question are you using the standard idas NBz or the UHS version. It would be interesting if it was the standard which would mean I can use mine in a tiny sensor Let me know

[@skyboy98046]

So then, how large have you printed your images taken with the rasa. I understand the cost of speed is a loss of resolution, hence cropping a small object from the wide field produces a grainy image for large scale printing. Yes? Also, I’m interested in your shot data on the images you displayed, number of frames at exposure. Do you by chance have a side by side comparison of the rasa vs. a standard 8” EdgeHD SCT? I have yet to ever see one. Nice review!!

[@paulhughes4527]

Great review, amazing images, looks like a fantasticly fast imaging system. I'm interested in the possibility of using a similar set up for EAA, would be interested in your thoughts on using the player 1 Uranus c as an option. Keep up the great work, clear skies, cheers Paul

[@jeffreyvictor3678]

Cody...could you achieve the same results using your Celestron EdgeHD 9.25" OTA and a Hyperstar? Reduces your SCT to f2.2. It saves you about $2000.00. Just curious.

[@offraed6156]

Yep. Also with an SCT or an Edge you can use it as a telescope, which you can't with a RASA. Why do people call these things telescopes when they are not. Its a lens, plain and simple. Where is the 'tremendous innovation' in the design? Its a spherical mirror with a Schmidt plate and a four element refracting correcting lens group. What is different about this to an SCT with Hyperstar?

[@SpaceCityAstro]

In the years you've had it, do you deal with mirror flop issues?

[@enriqueboeneker]

Great video, Cody!! Just one question about the ASI183: I’ve heard from a friend that the amp glow is bad... but is it?

[@AstroBlender]

Personally on mine it’s about the same as my 294MC Pro amp glow. It is removed by darks without any issue. It’s good to see the new ZWO cameras are getting much better in terms of amp glow (ASI 533MC Pro, also a good option on the RASA, 2600MM, etc.).

[@slzckboy]

I find it trivial to calibrate it out tho.

[@jeffginnow3561]

Your review pushed me over the edge and I have one of these on order. I'm thanking you, let's not ask my wife. 🙄. I have a question on the dew strap you're using. I use Astrozap equipment for my other scopes but am reading this review comment, " AstroStrap Dew Heater for 8" RASA - Seems well made but does not fit between the telescope tube and the one CGE mounting bar that comes with the 8" RASA. Will use it going on the outside of the CGE bar but it is likely less effective used in this way." I can see in the video you have a strap that fits nicely under both your orange CGE bars. What brand dew heater are you using? Thanks in advance for the help and keep up the good work!

[@AstroBlender]

Awesome, I’m sure you’ll enjoy it. I just love how fast I can image! I use DewNot straps on all my telescopes. AgenaAstro (link in description) has a size guide for all their straps.

[@MDSkytours]

Excellent review - thanks!

[@marcuslucchese2856]

Congratulations for the equipment, video and the explanation.

[@stevengross7984]

Excellent review! Wondering if, with such short exposures at f/2, a cooled camera is needed? What do you think about using the ASI183MC non-cooled rather than the cooled camera? Any experience with your ASI183MC-Pro with cooling turner off?

[@AstroBlender]

I personally always cool the camera to eliminate thermal noise. Even if I take 15 second exposures. I’d highly recommend the cooled route. You certainly could go with non-cooled and still get good results though.

[@houstonderk]

Great review. Is there a way to tell the difference in the V1 vs v2 as I see the new one has a different focus system.

[@frankgreen5005]

Cody, is that an ASI120 for autoguiding on top of your RASA8? Is autoguiding helpful with the RASA and, if so, would the ASI120 mini (and the little scope that comes with it as a package when ordering an ASIair Plus) be of use with the RASA8? Thank so much.

[@AstroBlender]

I’m using an ASI 178MM, but the 120mm/30mm Guidescope on the RASA would work great. The big advantage to guiding on the RASA is dithering.

[@frankgreen5005]

@@AstroBlender Marvelous, thanks again. Your videos are the best.

[@aprilbarton7852]

Would you consider it to be useful to drizzle an image taken with a large pixel camera to improve the undersampling? How do you find the quality of the drizzled image compared to a non-drizzled image with a smaller pixel camera? In my experience I've had a lot of success revealing new detail with drizzling to a pixel sampling more representative of the diffraction limit of the aperture.

[@AstroBlender]

Yes, drizzling will help for sure!

[@emranphy]

Fast optical system, but from your images, it seems that the shape of stars is not circular, which is, of course, one of the drawbacks hindering its practicality. I wonder if you can probe further into that in some comparison video.

[@HogarthsAstrophotography]

Nice review. Been considering a Rasa for a while.

[@AstroBlender]

Thanks!

[@MrPolicesnpr]

Great video!! Do you get the proper 25mm back focus with the 183MC pro and the Idas filter holder or do you need additional spacers? I'm just getting into this hobby and I really like your setup! Thank you for all the information.

[@AstroBlender]

The proper back focus with the IDAS filter drawer is to remove the optical glass, and then thread on the IDAS drawer and insert your filter. No additional spacers are required.

[@mickcarson8504]

Hi. Which is better for viewing close up of the moon mountains and craters, the RASA 8 or the Nexstar 8se?

[@Z-add]

They should make deepsky cameras that communicate using wifi or bluetooth and use replaceable lithium ion batteries. And get rid of both wires. Consumer cameras can do it why can't astrography cameras do it.

[@shubhkarmansingh2870]

Very informative video. How difficult is to take calibration frames with rasa? If possible, a video on calibration frames with rasa would also be helpful for likely buyers.

[@OlliesSpace]

Enjoyed the review lots of points covered for anyone considering this.

[@AstroBlender]

Thanks, that was the goal!

[@mickcarson8504]

What's the difference with RASA 8 and RASA 11? What about Nexstar 8se, is it any good?

[@stevel3o7]

I use a C8 with v3 hyperstar. I love the images but have a ton of vignetting (easily corrected in post) Do you find this with the RASA? Thanks for another great video.

[@AstroBlender]

No vignetting on my 4/3 or 1” sensor on the RASA. Keep in mind the RASA was designed for this purpose and had a huge illuminated circle, the Starizona HyperStar, although it works, it is an adaptation to an existing design.

[@jameskyler5441]

Cody, the 294 cameras "un-bin" to 2.315x2.315 at 4x the resolution so if you can deal with 89Mb images you can get great results with a wider FOV using 4/3 sensor

[@AstroBlender]

I knew the 294MM did, but wasn’t sure about the 294MC. Those images are far too large for me though.

[@hapestr]

Hi, thank you for a great review! I recently discovered your channel, and it's great! One question re the RASA8: Would it be possible to use planetary cameras, e.g. ZWO178MM, for this scope (of course with the FOV penalty)? My thinking is that as you can do significantly shorter exposures, thermal noise becomes less of a problem, and you get rid of one of the cables. Not sure about back focus, though, but would love to hear your thoughts. Keep up the GREAT work!

[@Jefferson196]

Good Review. I was thinking of purchasing a Rasa. As to a filter do you use the proprietary Celestron Light Pollution Filter made for the Rasa or something different. Thanks

[@AstroBlender]

I discuss filters towards the end, but yes, I do. :)

[@Jefferson196]

@@AstroBlender Ah..i missed that Thanks for the reply...

[@AstroBlender]

No problem! Take care, Cody

[@sanjeevjoshi6873]

Really good review. Some points from last few months of using it. AVX is actually just great, I use the 7.5 lb extra weight from Orion. I agree on APS-C - however the 2600 MC Pro with smaller pixels and much cleaner and less noisy sensor simply beats the 294 hands down. I use the 2600 for awesome wide field and the 183 MC Pro for details. With proper flats (using dark flats), you can eliminate the vignetting aberration completely. Nailing backfocus is the most critical aspect of the set up, and your enjoyment will depend a LOT on it, so good call out on that Astroblender.

[@AstroBlender]

Yeah the 2600 is an awesome camera, I was so close to pre-ordering a 2600MM, but couldn’t pull the trigger! I’m glad to hear the RASA 8 does well on your AVX.

[@craiglowery4427]

Very impressive. Can it do planetary

[@mohamedalmaazmi3676]

Great video 🙏🏼 .. just one question.. any issues with Collimation when using RASA ? If so have you done any collimation adjustment ?

[@AstroBlender]

I haven’t had a need to adjust collimation. That may be due to my use of a 1” sensor, but it holds collimation very well.

[@mohamedalmaazmi3676]

@@AstroBlender Many thanks 🙏🏼

[@cometspeed3502]

Hi Cody, great review. Would the Celestron LPS filter be a better option than the Optolong L-Pro and the Idas LPS-D1 that I've been using now ?

[@AstroBlender]

I would think so, the Celestron LPS filter is purpose built specifically for the RASA. I've had incredible results with it. I took a couple images with my IDAS LPS-D2 and the RASA LPR, and the RASA LPR had more contrast and less of a gradient. I haven't used my Optolong L-Pro in the RASA as I never felt a need to do so. That's just my 2 cents.

[@cometspeed3502]

@@AstroBlender Thanks Cody.

[@AstroBlender]

You bet.

[@cometspeed3502]

@A L The Optolong L-pro is a light pollution filter and the NBZ a narrowband filter.

[@vladimirmachek2524]

Very nice, very informative. Thank you 👍

[@AstroBlender]

Thanks, glad you think so!

[@andrebergeronastro]

In your video you said that we can use rasa8 without guiding, I would like to see how to do that with asiair pro. Thanks

[@BLastrophoto]

Great video! Now subbed to your Instagram. I'm considering a RASA 8 for my next wide field scope. Figured it would do Luminance beautifully while my ED80 at 390mm does RGB. Looking forward to seeing more results with this scope! Great work!

[@AstroBlender]

Oh, thanks! Yes, that would make a great combo. Especially because you could piggyback the ed80 on the RASA8 and run that simultaneously! :)

[@BLastrophoto]

@@AstroBlender Exactly what I was thinking! Slap both of them on the EQ6-R Pro, OAG guiding with the ED80, call it a day. Thanks for the input! Makes me feel a bit more confident with my thought process here.

[@AstroBlender]

Yep, and at 400mm flexture between the ED80 and the RASA 8 won’t really have a big impact on your guiding. Good luck with your decision - for what it’s worth I love the RASA 8!!!

[@rosaluks644]

A nice review! F/2 of course is good to have, but the usefulness of a low f/# is going to be limited by light pollution. If your signal is light pollution limited, then having a faster scope is not going to be very effective I think

[@ElemeStudios]

How is it that the ASI183MC is a 1 inch sensor, the specs show that this camera has a 15.86 mm diagonal chip size. Are they referring to the optical window being 1" in diameter and not the sensor size?

[@AstroBlender]

The sizes of sensors are named after old video cathode tubes and they never changed. The diameter of one of the old cathode ray tube was 1”, but sensitive area was only about 0.60”. They still use this terminology to describe sensors today even though it is not accurate. Same with Micro 4/3”, 1/2” etc. they’re all just describing the diameter of a cathode tube equivalent, not the actual useable area. The useable area is much smaller than the name.

[@patbrubeck3313]

I understand that collimation of RASA’s is pretty difficult. Have you had to collimate your telescope, and, if so, how difficult is it? Would the challenge of collimating the scope be a factor in avoiding buying one?

[@AstroBlender]

I haven’t had to collimate it no, it holds collimation very well. The primary angle is fixed, and only the lens element what needs collimation. It also helps that I use a 1” sensor so I don’t see the effects as much.

[@divye.ruhela]

Bin mode on 294MC Pro must kill it with the RASA?

[@bombervero929]

Congrats for this great review! How do you manage to take dark and flat frames with this setup? Thx!

[@AstroBlender]

Dark frames I don’t take on the telescope. I just use my dark frame library. Flats I use a cheap homemade panel that my wife came up with. Video on this is coming soon!

[@CDigata]

where is the focus point on the focus, is it around midway or more towards 1 direction fully.

[@davejenkins8524]

I have a RASA 8 and a Baader filter drawer. works great. is there an adapter/perverter that will allow the Celestron filter to be used the filter tray. so you can just slide as in and out?

[@davejenkins8524]

Is there a 3d printed scope cover that is 'top hat ish' to fit over the RASA and the camera? or is there one that will fit over the end of the dew shield confidently?

[@MrSummitville]

Why did you add noise to your audio track. Explain how, adding background noise makes easy to hear what you are saying?

[@deepd4393]

Won’t the OSC camera wires block the lights?

[@ericgoz3858]

Very informative and well done. You sold me Hello Celestron RASA 8 :)

[@AstroBlender]

That wasn’t my intention with a review, more to help buyers with information they need to know. That being said, there is a reason it is my go-to imaging scope! :)

[@veeretsy7528]

I think you should try the cygnus wall

[@slzckboy]

This was the camera I went for with my hyperstar because of the image scale as you say.I nearly went mono but I kept reading that these fast focal length setups can shift the bandpass of filters thus making narrow band filtering more challenging.. I need to look into this more but for example an optolong enhance is better suited to these than the optolong extreme because of its wider bandpass?! This is hearsay on my behalf.

[@AstroBlender]

It’s true! I have a few videos showing the L-eXtreme at high speed, and it doesn’t work well. If you do monochrome I have a few buddies that use the Baader high speed f/2 filters and they produce great results.

[@AstroDenny]

I love my RASA, but I have to disagree that the front mounted camera makes filter changes easy. I think for a dedicated astrograph, the filter system is kinda crap. I got th e Starizona filter slider and that helped a lot. I also have the Celestron CLS filter and I found it to be overpriced and it was really hard to correct colors in post with it. Rounding out the filter problems- The F/2 optics make narrow pass filters not behave right so there's an added expense of getting filters rated at F/2. The Optolong L-eNhance works- The L-eXtreme and Radian quad band do not. The cooling fan is nice but mine is already making noise and I suspect it will fail in the next few months. I also had a hard time taking good flats- I set up a white screen at home but then I need to leave my camera on the scope until I can take my flats so I have to leave the cover off while I transport it- Definitely not ideal. Despite all the challenges, I am still addicted to the speed factor of F/2 imaging!

[@AstroBlender]

You definitely make some great points. I agree on the L-eXtreme. I made two videos on the subject that got some interesting response. Flats are tricky some people put a flat panel on top of the dew shield, others take night flats. All good points. I haven’t had that issue with my fan yet.

[@bhammy1565]

Just got the Radian Quad a few weeks ago, only one session with it so far, but I've experience GREAT results with it during 88% moon.

[@deepd4393]

Could you please explain how to do calibration frames for Rasa8?

[@majesticreefs]

Cody, my RASA is on the AVX I would love not have to guide but I get walking noise if I don't guide and dither. Do you have a solution to avoid the walking noise without guide and dither?

[@AstroBlender]

I wish I did, but dithering really is the best way to do that. Dithering helps eliminate hot pixels too. A good set of darks will obviously go a long way, but dithering is definitely a benefit to autoguiding.

[@RostGlukhov]

Awesome review and description, thank you!

[@AstroBlender]

Glad it was helpful!

[@AndrewThomas73]

I was wondering if you could do a video on dithering, I know there are tons on KZbin, but most don't go into the settings like dithering distance and scale, most on KZbin are just front of house sales people for new products. We need more factual based astro photography videos

[@AstroBlender]

Hi Andrew, I can add it to the list for you! - Cody

[@AstroPixUK]

Great video. This is my dream scope. Got a wedding to pay for first 😂😂😝

[@AstroBlender]

Hahah congratulations! But that sucks at the same time! 😅

[@DavesAstrophotography]

Great review Cody.

[@AstroBlender]

Thank you, Dave!

[@gunnarjensen5910]

No collimation problems ?

[@andyweeks2216]

Really nice Cody!

[@AstroBlender]

Thank you, Andy!

[@OverGlown]

I actually loved it.😊 thanks

[@surinderparkash1135]

A great review. Subbed 👍

[@AstroBlender]

Glad you enjoyed it, thanks.

[@veeretsy7528]

you could optionally go for a c8 and hyperstar

[@ericemanuelson5128]

Great review!

[@AstroBlender]

Thanks! I am glad you enjoyed it.

[@amolgitapathi]

Cannot use visually?

[@GabrielV3]

How would you compare it vs the 8 sct with the f2 focal reducer please?

[@AstroBlender]

Both work well. This is a dedicated system though, so less collimation typically, less vignetting, and superb color correction.

[@dr.feelgood374]

What guide scope and camera you using with this setup?

[@AstroBlender]

Stellarvue 50mm Guidescope and a ZWO ASI 178MM

[@dr.feelgood374]

@@AstroBlender Thank You for the reply. Just purchased the RASA 8 after watching you video, was on the fence about it but got to see it in action and figured I'd add it to the collection. Tried using your link but they were out of stock went to Highpoint at got one. Thanks again.

[@classiccuisine7001]

How do you like the CGX mount?

[@AstroBlender]

I like it, but I need to work out some guiding issues. My Dec is always phenomenal, about 0.20”, but RA I’m usually about 1.50”. I’m just waiting for it to get warmer before I start making some adjustments.

[@damiencannane]

Hi there! I have the same camera/scope combo, and I just added the same focus motor (using your install video for reference!) What is your autofocus step size? I'm hoping to get out under the stars tomorrow night and I would expect that your step size will work for me as well. Thanks!

[@selfworthy]

Why didnt you just convert your Celestron SCT with a Hyperstar to get F1.9 ?

[@AstroBlender]

Although both good options, the RASA is a better instrument if you can afford one. It is purpose built for f/2 imaging, having less vignetting then HyperStar, better color, and less issues with collimation. HyperStar does work well for those that use them, but I knew I would be using f/2 so much I wanted a dedicated system.

[@davidbright8978]

But how does it work with mono camera where you need to use color filters.

[@AstroBlender]

Even better! I wish I had a mono camera, but I don’t, unfortunately. Many people use the Starizona filter drawer and image in H-alpha, S-II, and O-III and produce stunning results.

[@skyboy98046]

Why is F2 better if you loose resolution? 🤪

[@maximkosheleff]

Are wires on a problem? Don't use them!! Wireless USB is available. Also powerank just after a camera will help u

[@stxe34]

you kind of look like captain america before the op ;) great vid!

[@AstroBlender]

Haha you’re like the fourth person that’s left a comment like that. I’ll take it as a complement I suppose!

[@stxe34]

@@AstroBlender yep, i have a question...what is the eaf focus like? i have the edge 8 with hyperstar and as you know focus is crucial! i love the asiair pro!

[@AstroBlender]

It’s excellent, I just get the stars in view, press autofocus and it does the rest for me. I also set it to re-focus every hour, or every 1 degree change in temperature. It works so well, I plan on putting it on all my astrophotography telescopes.

[@stxe34]

@@AstroBlender thanks bud, what would be great if you could do detailed vid of collimation.

[@astrodude42]

@@AstroBlender Hi Cody, is it necessary to turn the focus knob counter-clockwise as a last step, like with the EdgeHD 8“ and bigger SCTs? i have an EdgeHD 8“ and cannot get the scope to stay in focus after autofocus using the ASIAir Pro and the EAF. i finally removed the EAF, focus manually and lock the primary mirror. I see a lot of SCTs with EAF and it seems like i am doing something wrong. Any help would be greatly appreciated.

[@ColeDedhand]

There are no mirrorless DSLRs. There are mirrorless cameras. The R in DSLR stands for Reflex, which is a mirror. So a mirrorless design cannot be a DSLR and a DSLR cannot be a mirrorless design.

[@markissboi3583]

Talk all yah want Here to see the view 12:56🤔 Good pics now i dont have to buy one thanks ✔ Celestron RASA 8 $au ooh $3k the 36 otr $29k eeeh buy a 2nd hand electric car