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Info needed - using the WO RedCat 51 for deep sky imaging

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#1 jsnatale

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Posted 17 October 2021 - 08:46 AM

I am considering getting the William Optics RedCat 51 for deep sky imaging. I would piggy-back this scope onto my existing CPC 800 HD Edge scope, so I could have deep sky imaging capability with very wide field views. The RedCat got great reviews so I am seriously considering it. I would like to be able to image the larger deep sky objects, such as the Orion Nebula and Andromeda galaxy, and also fit the entire moon in the field of view.

 

If any of you are familiar with the RedCat, can you provide some input on the following:

 

1. Is this a good telescope for deep sky imaging?  Or should I go with a slightly larger scope? The lens is only 51mm, and the focal length only 250mm. I would use it in conjunction with a ZWO asi 294, 533 or 183 camera- haven't decided yet.

2. If you own this telescope and have had any issues with it, what are they?

3. If there is another telescope you would recommend over the RedCat, which would it be, and why?

4. Would it be possible to use this scope as a guide scope in the future, if I decide to use it for that eventually?

5. Weight is a consideration since I would be piggy-backing it on my existing CPC 800 scope. Do you think its weight (at 2.9  lbs) would be a problem?

6. If you have any deep sky images you have taken with this telescope can you please attach them? 

 

Thanks. Here is a web link to the RedCat:

 

https://www.highpoin...762c02310652cc1


Edited by jsnatale, 17 October 2021 - 09:55 AM.

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#2 terrypaula

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Posted 17 October 2021 - 09:08 AM

From what I've read about the Red Cat 51 is that it's better suited for wide field AP then it is for Deep Space Imaging,  I was using a TS503ed, 50mm @330fl. and I was able to get some fantastic images of the Heart & Soul nebulas in the same frame.


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#3 jonnybravo0311

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Posted 17 October 2021 - 09:13 AM

The Cats are nice scopes and many people have used them to create very nice wide field images.

 

Your biggest limitation for deep sky imaging right now is your mount. The CPC system is an alt-az mount. Great for visual astronomy, not so much for deep sky imaging. Field rotation is what's going to be your primary concern. I don't know if there's some kind of wedge system available, but you might want to look into that.

 

I'm not sure what cameras you mean... two of the three you mentioned don't exist. Were you meaning to ask about the 294, 533 and 183? If so, my choice would be the 533. It's the better sensor of the three.

 

One of the advantages of the Cat is the design. You don't need to purchase or use a separate flattener/reducer because it's built into the scope. A downside, for some, is the focusing mechanics. Unlike more "traditional" systems with dual course/fine knobs, the Cats use a helical focuser very similar to a camera lens. In fact, the Cats actually make pretty decent little 250mm primes for terrestrial use (birding in your backyard for example).


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#4 Topographic

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Posted 17 October 2021 - 09:31 AM

Check out the images from the Redcat users group on Astrobin.


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#5 bobzeq25

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Posted 17 October 2021 - 09:37 AM

I am considering getting the William Optics RedCat 51 for deep sky imaging. I would piggy-back this scope onto my existing CPC 800 HD Edge scope, so I could have deep sky imaging capability with very wide field views. The RedCat got great reviews so I am seriously considering it. I would like to be able to image the larger deep sky objects, such as the Orion Nebula and Andromeda galaxy, and also fit the entire moon in the field of view.

 

If any of you are familiar with the RedCat, can you provide some input on the following:

 

1. Is this a good telescope for deep sky imaging?  Or should I go with a slightly larger scope? The lens is only 51mm, and the focal length only 250mm. I would use it in conjunction with a ZWO asi 297, 553 or 183 camera- haven't decided yet.

2. If you own this telescope and have had any issues with it, what are they?

3. If there is another telescope you would recommend over the RedCat, which would it be, and why?

4. Would it be possible to use this scope as a guide scope in the future, if I decide to use it for that eventually?

5. Weight is a consideration since I would be piggy-backing it on my existing CPC 800 scope. Do you think its weight (at 2.9  lbs) would be a problem?

6. If you have any deep sky images you have taken with this telescope can you please attach them? 

 

Thanks. Here is a web link to the RedCat:

 

https://www.highpoin...762c02310652cc1

Note that there are two issues.

 

How good is it do _do_ imaging?  Very good, with the right targets (largish ones).  Many people have made some lovely images with one.

 

https://www.astrobin...earch/?q=Redcat

 

How good is it to _learn_ DSO AP with?  Excellent, one of the very best choices.

 

As pointed out, a good mount is necessary for imaging.  It's the most important part of the setup.  But, the Redcats 250mm focal length makes it quite forgiving.  The CPC on a wedge is one possibility.  People do use $300-500 camera trackers also.  Of course a GEM mount is best, but it can be one of the lower end models.

 

Here's someone who went all out with a Redcat.  GEM, mono camera, narrowband filters.  Note the quality of his Redcat image.  Note was he says about how he enjoys imaging with the Redcat.  That's important, this can be a very frustrating hobby.  <smile>

 

https://www.youtube....h?v=MNQU1hdqz4M

 

Bottom line.  I highly recommend this scope.  Especially if you are new to DSO imaging.  In that case, four more recommendations.

 

This will be the best $44 you ever spend on DSO AP.  <smile>

 

https://www.amazon.c.../dp/0999470906/

 

Astro Pixel Processor.  The "free" alternatives are not free in terms of your time, frustration level, and image quality.

 

Don't omit the camera calibration frames: bias, flats, lights.  They're not some advanced technique, they're fundamental.

 

I support the recommendation above for a 533 camera.  One of the easiest to use.  Don't worry too much about image scale.  But' it's only available as one shot color.  Id you do want to go the more expensive route of mono and filters, the 183 and 294 come in both types, I'd give the nod to the 183 with a Redcat, the 294 as a more general purpose camera.

 

About using it as a guide scope.  It can work.  But note that, if you ever want to image with the big SCT, you'll need serious experience with the Redcat first.  And an expensive mount.


Edited by bobzeq25, 17 October 2021 - 09:57 AM.

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#6 jsnatale

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Posted 17 October 2021 - 09:59 AM

Thanks everyone. JohnnyBravo - you are right- the cameras I was referring to were the asi 294, 533 and 183... sorry for the typos.. I fixed them in my original post.


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#7 DesertCrawler

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Posted 17 October 2021 - 12:28 PM

1. That's perhaps subjective. If widefield is for you, then yes, it is good. It will handle a FF sensor with some vigneting that calibrates out, and an APS-C is no issue. Nice feature set.

2. No issues with the OTA to date. The felt adhesive ring on the lens cap became unglued. W.O. sent me a replacement felt strip.

3. There are comparison videos out there I believe. I liked the idea of the Petzval design and it does not disappoint.

4. Guide scope, why not.

5. I currently use an AT66ED, a decent imager in its own right, as a guide scope on my RASA 11 and used it briefly on a C9.25XLT before I went to OAG. It is heavy, but so long as the mount and attachment hardware can handle it, no worries.

6. Check your PMs.

 

I like having mine around. I don't use it that much but have specific plans for it similar to what you laid out. I have set it up on a ZEQ25 while imaging other things just to see what I can get.

 

I use the ProAstroGear focus system with a ZWO EAF. It is superb. Near zero backlash and rivals as the most reliable focus system on any of my scopes. It never fails to find repeatable focus in NINA.

 

I guide it with either a SlideBase32 or SlideBase50 and sometimes unguided depending upon various conditions.

 

Bang for the buck, I think it is hard to go wrong if widefield is what you're after.

 

Good luck with the hunt and the decision.

 

I am considering getting the William Optics RedCat 51 for deep sky imaging. I would piggy-back this scope onto my existing CPC 800 HD Edge scope, so I could have deep sky imaging capability with very wide field views. The RedCat got great reviews so I am seriously considering it. I would like to be able to image the larger deep sky objects, such as the Orion Nebula and Andromeda galaxy, and also fit the entire moon in the field of view.

 

If any of you are familiar with the RedCat, can you provide some input on the following:

 

1. Is this a good telescope for deep sky imaging?  Or should I go with a slightly larger scope? The lens is only 51mm, and the focal length only 250mm. I would use it in conjunction with a ZWO asi 294, 533 or 183 camera- haven't decided yet.

2. If you own this telescope and have had any issues with it, what are they?

3. If there is another telescope you would recommend over the RedCat, which would it be, and why?

4. Would it be possible to use this scope as a guide scope in the future, if I decide to use it for that eventually?

5. Weight is a consideration since I would be piggy-backing it on my existing CPC 800 scope. Do you think its weight (at 2.9  lbs) would be a problem?

6. If you have any deep sky images you have taken with this telescope can you please attach them? 

 

Thanks. Here is a web link to the RedCat:

 

https://www.highpoin...762c02310652cc1


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#8 ngatel

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Posted 17 October 2021 - 12:56 PM

The RedCat generally gets really good reviews. I got serious about astrophotography last year, but my only scope, at the time, was a C8 on a NexStar SE mount. I decided, correctly, I needed a new mount, and a C8 would be a painful learning experience.

 

So I bought a CGX and a ZenithStar 61 connected to a Sony A6000. The learning curve for capturing images was short. Within a couple of months I was able to do fairly well with the C8 on the CGX. Then I got a ZWO ASI183 MC Pro. Things got easier. Then I bought an Esprit 100 and a ZWO ASI071MC Pro. 

 

Today, with whatever combination of scope and camera I use, I get excellent data. The only challenge is refining my post processing skills. That is just a time and experience  factor. Each month I get a little better.

 

I suspect that had I started with the C8 for imaging, I would have given up. I am so glad I started with the Z61, as the wide FOV is forgiving of many learning issues.

 

Today I do most of my imaging with the Esprit, then the Z61, and lastly the C8 — it all pretty much depends on the target.


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#9 jsnatale

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Posted 17 October 2021 - 12:57 PM

It sounds like the RedCat (piggy-backed on my CPC) is the way to go - thanks everyone again for your info. Your comments confirm the previous good reviews of it I have seen. I do, however, have another question. A few people have brought up the importance of getting a wedge for my CPC. I checked into it, and am wondering if it is worth the cost/effort. My CPC is already very heavy (at 40 lbs), and the wedge (link below) is an additional 38 pounds. That is a lot of weight/effort for setting up!  As it is, I have quite a time lugging around the CPC and "heaving" it up onto the mount... adding in the wedge, it would be a real project to set up! Plus the wedge, from what I heard, would need to be calibrated/adjusted each time I used it, and it is expensive at over $400. 

 

I am thinking about getting the RedCat, the appropriate asi camera (asi 533?), and using "Live Stacking" in Sharpcap Pro for imaging, at least for now, and not getting the wedge. Live stacking was designed for those of us with alt-az mounts that haven't made the full move into deep sky, but want to see decent (not necessarily phenomenal) deep sky images (like me). With live stacking you just use short exposure times- say 5-15 seconds- and you see the image appear as you are stacking. Would the wedge really be that useful using these short exposure times?

 

https://www.amazon.c...821831351&psc=1

 

Note - when I bought the CPC 800 I had no idea it was not suited for deep sky astrophotography (I am just starting out at this). I also didn't know how much I would like astrophotography - I much prefer it to visual astronomy. If I had known I would have gone for an apo refractor and GEM mount. Well, hind sight is 20-20... now I am trying to make the best with what I have, just trying to get decent images of deep sky objects and planets with my CPC. But I will say that my CPC/asi 224 are excellent for lunar and planetary photography- just terrible for deep sky/wide field. 

 

Let me know if anyone has any more comments about the wedge. I could go either way on that. If I don't get many replies, maybe I'll post this subject as a separate posting.  Thanks again. 


Edited by jsnatale, 17 October 2021 - 01:00 PM.


#10 jonnybravo0311

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Posted 17 October 2021 - 01:03 PM

It sounds like the RedCat (piggy-backed on my CPC) is the way to go - thanks everyone again for your info. Your comments confirm the previous good reviews of it I have seen. I do, however, have another question. A few people have brought up the importance of getting a wedge for my CPC. I checked into it, and am wondering if it is worth the cost/effort. My CPC is already very heavy (at 40 lbs), and the wedge (link below) is an additional 38 pounds. That is a lot of weight/effort for setting up!  As it is, I have quite a time lugging around the CPC and "heaving" it up onto the mount... adding in the wedge, it would be a real project to set up! Plus the wedge, from what I heard, would need to be calibrated/adjusted each time I used it, and it is expensive at over $400. 

 

I am thinking about getting the RedCat, the appropriate asi camera (asi 533?), and using "Live Stacking" in Sharpcap Pro for imaging, at least for now, and not getting the wedge. Live stacking was designed for those of us with alt-az mounts that haven't made the full move into deep sky, but want to see decent (not necessarily phenomenal) deep sky images (like me). With live stacking you just use short exposure times- say 5-15 seconds- and you see the image appear as you are stacking. Would the wedge really be that useful using these short exposure times?

 

https://www.amazon.c...821831351&psc=1

 

Note - when I bought the CPC 800 I had no idea it was not suited for deep sky astrophotography (I am just starting out at this). I also didn't know how much I would like astrophotography - I much prefer it to visual astronomy. If I had known I would have gone for an apo refractor and GEM mount. Well, hind sight is 20-20... now I am trying to make the best with what I have, just trying to get decent images of deep sky objects and planets with my CPC. But I will say that my CPC/asi 224 are excellent for lunar and planetary photography- just terrible for deep sky/wide field. 

 

Let me know if anyone has any more comments about the wedge. I could go either way on that. If I don't get many replies, maybe I'll post this subject as a separate posting.  Thanks again. 

You nailed it on the head when you stated that your current setup is good for lunar/planetary but pretty terrible for DSO imaging. You could probably get some decent end results with EAA and live stacking using your existing setup and 533 (no wedge). I'm not too familiar with such setups, but you could probably ask in the EAA forum where people with much more experience than I have will steer you in the right direction :).


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#11 ngatel

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Posted 17 October 2021 - 01:03 PM

When I bought my CGX equatorial mount, I thought about a wedge for the NexStar SE. Most people advised against it and say they couldn't get it to work. But then I saw some excellent images from a few folks using it. So a wedge can work. But the learning curve is steep, plus you really need to guide.

 

With the RedCat you can buy a "star tracker" mount for about what that wedge would cost, and you would probably learn quicker and be happier with the results than with what you propose.

 

Go to astrobackyard.com or his YouTube channel. Lots of information for beginning people using small refractors like the RedCat, or even camera lens to capture images.


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#12 bobzeq25

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Posted 17 October 2021 - 06:12 PM

It sounds like the RedCat (piggy-backed on my CPC) is the way to go - thanks everyone again for your info. Your comments confirm the previous good reviews of it I have seen. I do, however, have another question. A few people have brought up the importance of getting a wedge for my CPC. I checked into it, and am wondering if it is worth the cost/effort. My CPC is already very heavy (at 40 lbs), and the wedge (link below) is an additional 38 pounds. That is a lot of weight/effort for setting up!  As it is, I have quite a time lugging around the CPC and "heaving" it up onto the mount... adding in the wedge, it would be a real project to set up! Plus the wedge, from what I heard, would need to be calibrated/adjusted each time I used it, and it is expensive at over $400. 

 

I am thinking about getting the RedCat, the appropriate asi camera (asi 533?), and using "Live Stacking" in Sharpcap Pro for imaging, at least for now, and not getting the wedge. Live stacking was designed for those of us with alt-az mounts that haven't made the full move into deep sky, but want to see decent (not necessarily phenomenal) deep sky images (like me). With live stacking you just use short exposure times- say 5-15 seconds- and you see the image appear as you are stacking. Would the wedge really be that useful using these short exposure times?

 

https://www.amazon.c...821831351&psc=1

 

Note - when I bought the CPC 800 I had no idea it was not suited for deep sky astrophotography (I am just starting out at this). I also didn't know how much I would like astrophotography - I much prefer it to visual astronomy. If I had known I would have gone for an apo refractor and GEM mount. Well, hind sight is 20-20... now I am trying to make the best with what I have, just trying to get decent images of deep sky objects and planets with my CPC. But I will say that my CPC/asi 224 are excellent for lunar and planetary photography- just terrible for deep sky/wide field. 

 

Let me know if anyone has any more comments about the wedge. I could go either way on that. If I don't get many replies, maybe I'll post this subject as a separate posting.  Thanks again. 

This is pretty simple.  It's NOT a question of image quality (a common misconception).  It's a question of if you want to go on a path that could lead somewhere.  If you just want to get something and don't care about getting better in the future at all, use alt-az.  It's a dead end.  Time spent fussing with it is wasted time for doing something more.  You'll exit the experience not knowing if, with more suitable equipment, you'd have liked DSO astrophotography. 

 

If you think that this is something you might want to pursue father, you need an equatorial mount.

 

My advice is not geared at the idea of images of any particular quality.  It's aimed on putting you on a path that you can follow as far as _you_ want to.  The alt az doesn't do that. 

 

I quite agree sticking the Redcat on top of a CPC800 on top of the wedge is cumbersome.  But it's way better than no wedge.  Better options than the wedge.

 

The  Youtube video I referenced uses a mount similar (functionally) to this.

 

https://www.highpoin...to-mount-s30400

 

It would be excellent with the Redcat51 as a starter setup.  And, if you want to go farther, could take anything up to an 80mm.  I recognize that it may be too expensive.  But, heads up.  DSO imaging is expensive.

 

The inexpensive option is this.  No DEC motor (with good polar alignment and 250mm you can get away with that).  No GOTO.  It would work OK with the Redcat as a starter setup.  But you'd need to replace it to go farther.

 

https://milehighastr...ro-full-package

 

Note that you'd need a tripod.

 

It's simply not intuitive how important the mount is.  The camera is good only if you can keep it precisely pointed during an exposure.  The forgiving nature of the Redcat gives you two inexpensive options.  The wedge, and the skyguider pro or similar.  The one I referenced is in stock, no small thing these days.

 

Another option is Electronically Assisted Astronomy instead of traditional imaging.  You could use the CPC800 alt az.  There's a separate forum here, you can get advice about EAA there.


Edited by bobzeq25, 18 October 2021 - 09:32 AM.

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#13 Ryou

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Posted 17 October 2021 - 06:46 PM

I've actually been using my SpaceCat, which is just a recolor of the RedCat, the past few nights. I also used it when I was starting out along with a 183mm. More recently I've gone "all out" (as another poster put it here) with full LRGBSHO filtering. Admittedly I still need to get an AF setup, however even w/o that I'm very happy with some initial LRGB imaging I did of M31.

 

Everyone has already given great advice so I don't really have much to add, however I do 100% suggest going to some form of Field of View Simulator (Stellarium has one built in, for something more web oriented look at telescopius) and try it out with the cameras you said. The 183 pairs beautifully with the Cats for a lot of the larger objects. Even some of the smaller objects (see my above link to the Bubble Nebula, which is smaller in scale) will still turn out very nicely.

 

There are of course trade offs between the Cat and a deeper scope, however this is true in general in this hobby since there is not a one sized fits all approach. From a learning perspective it's super forgiving and can help you get good fundamentals along with wanting to go deeper.

 

Also, buy once cry once. Learn it when thinking about this hobby or you'll be spending a lot of needless money. Mount mount mount mount is the biggest thing you can do to start. Sure it won't matter as much wide, however if you start going into Galaxies or smaller DSO then you'll likely be going deep enough where it matters.


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