NexStar 6se EAA Recommendations

[Todd1561]

Hi everyone,

I've only recently gotten into astronomy and have learned a lot from this forum so far.  I have a Celestron Nexstar 6se on it's stock AltAz mount.  Given my techie background, desire to automate (and probable laziness!) I think that EAA for instant gratification and sharing the hobby with friends and family is a good fit for me.  I'd also like to be able to record frames as I'm viewing "live" for later post-processing for even greater results.  At this point I'm looking for suggestions on a camera to use with my scope to hopefully reach my goals.  I realize there's no one size fits all in this hobby, but a combination that can provide decent results that I won't immediately outgrow would be ideal.  My interest would be planetary/lunar and DSO.  I see myself spending more time on DSO as I grow.  My primary viewing location is my house in suburban North Carolina.

From the research I've done so far I've come up with these contenders:

- ZWO ASI224MC  (everyone seems to love this cam, great for planetary, but small resolution/chip for DSO)

- ZWO ASI178MC (seen some claims that the pixel size is too small for my SCT @ f/10.  Would a f/6.3 FR help enough?  Slightly larger sensor is more appealing to me for DSO.)

- ZWO ASI174MC  (largest chip out of the lot)

- ZWO ASI290MC

- Or another camera that's recommended in this price range, I'm not married to ZWO, they just seem to have come up frequently in my research.

I'm also thinking I should use the Celestron f/6.3 focal reducer for DSO regardless of the camera for a wider FOV and to speed up the scope, do you all agree?  AFAIK that's the only focal reducer for this scope, otherwise I'd probably go further.

Final question, should I put much weight on cooling?  That seems to about double the price tag for what is essentially a heat sink and a fan.  Can that be retrofitted later if I find it necessary?

My apologies if this question has been asked before.  I found a lot of information but it seems to be very specific to the hardware you already have so I wanted to be sure to get opinions specific to a 6se scope.  The tech also seems to be changing rapidly so wanted to get the latest information.

Thanks for any help!

[noah4x4]

Hi Todd,

The lack of responses and images in the galleries perhaps confirm to you that a Nexstar SE6 is not a popular choice for more serious Astrophotography or EAA. No disrespect intended, but it's probably not worth investing in a seriously expensive camera unless planning to improve your aperture and mount. The more you pay for a camera (example, larger sensor + megapixel + cooling) then potentially the better the results. However, there isn't a lot of sense in going to a top end specification camera for it to then be limited by the modest aperture of a Celestron 6" SE  and the general limits of the Alt-Az 6SE mount.

You will ideally want to reduce focal ratio by a reducer or Hyperstar, but the SE 6" is limited. Buying Hyperstar for a SE6 doesn't make sense as unlike most accessories you can't then transfer it to a larger OTA, plus you are limited to narrow barrel cameras. So the regular Celestron f/6.3 focal reducer is probably your sensible limit as regards practicality and expense.  But once again, there is no point in spending a bucket load of money on a mega-camera as the FOV will still remain limited (compared to F2 on Hyperstar or an 8" or greater SCT with reducer).

You next issue is length of exposure and tracking. An SE6 isn't  that robust (wind shake etc)  and any Alt-Az without wedge (or Hyperstar) limits you to extremely short exposures. You are not going to avoid star trails if trying to capture many DSO's. However, with software that stacks even the cheapest camera that you have mentioned will offer nice planetary and lunar images and can be used for EAA on brighter objects like the Orion Nebula (which can typically be seen in 2 second exposures). Don't waste money on a wedge. It is an infernal beast to tame. A GEM mount is much better, or do as I did and skip straight to Hyperstar if an existing owner of an 8" or larger SCT/Alt-Az. But having bought a 6" SE you are limited. 

What I am trying to say is don't waste a lot of time or money fretting about this cemera choice. Simply enjoy. Buy the least expensive camera that you know (from the image galleries) can produce some nice images that meet your expectation then later invest in more pixel power only after upgrading your mount/aperture. You can't make a silk purse out if a sows ear. You can always use your entry level camera later as a guider when you do upgrade.There is an excellent guide to ZWO cameras on the Agenaastro.com website that highlights suitability for planets and DSOs.

[Todd1561]

Hi there, thanks for the honest response and the thoroughness.  I see what you're saying about this setup not being ideal, I'm sure it won't be the last scope I own but at least at the time seemed like a good starting point without investing a whole lot to see if I enjoyed the hobby.  In the time since I created this thread I think I've landed on the ASI224, from what I can tell it's a decent entry level camera that won't break the bank and I can always use it down the road for guiding as you point out.  I think I'll pick up a 0.5x focal reducer to try and squeeze even more FOV and speed the scope up to f/5.  They're also pretty inexpensive compared to the SCT reducers and should allow me to get my feet wet with EAA without over investing in this setup as you suggest.

[stash_old]

If you want to see what a 6inch scope can do  with say a Lodestar x2 search EAA for Hilodon picures which were taken with an Hyperstar on a Celestron Evolution 6. Also look in  EAA for Altair RC6 (ok its a Ritchey Chreiten) images(sorry cant remember who - RobertI ??)) to give you an idea of what can be achieved!!!!!

[Robrj]

I think the 224 would be a good choice.  Although the chip isn't that large, it's large enough for live viewing (1304x976).  Other than extended nebulae, most objects will be small and should fit in the field of view.   If you want a slightly bigger chip, another option is the ASI385MC (1936x1096).  It's similar in sensitivity to the ASI224MC but with a slightly larger chip.  The only real issue with a smaller chip is if you ever want to print an image, it will be small.  But since we're live viewing that wouldn't really be much of an issue.

 

[noah4x4]

I was never saying that good results are not possible with an SE6 - simply that there is no particular benefit in buying a high end very expensive camera until other factors are improved.

Stash-old, you mention great results from an SE6 on Hyperstar. I concur that Hyperstar is superb with any Alt-Az except  that on a 6" you are limited to narrow barrel cameras. But if the OP did spend $700 on the 6" version of Hyperstar he would then need to spend another $900 if he later graduated to an 8" scope or $950 for a 9.25" because unlike most other accessories Hyperstar is not transferable between scopes of different sized OTAs. 

My wider point was hence settle on mount/tripod/OTA first and only commit expense propotionate to its capabilities. I think that advice is sensible whether buying cameras, eyepieces or similar. How many of us have boxes full of redundant kit such as 1.25" eyepieces and filters when we are now requiring 2"?

I too think the AS1224 was a good choice considering the factors.

[stash_old]

3 hours ago, noah4x4 said:

I was never saying that good results are not possible with an SE6 - simply that there is no particular benefit in buying a high end very expensive camera until other factors are improved.

Stash-old, you mention great results from an SE6 on Hyperstar. I concur that Hyperstar is superb with any Alt-Az except  that on a 6" you are limited to narrow barrel cameras. But if the OP did spend $700 on the 6" version of Hyperstar he would then need to spend another $900 if he later graduated to an 8" scope or $950 for a 9.25" because unlike most other accessories Hyperstar is not transferable between scopes of different sized OTAs. 

My wider point was hence settle on mount/tripod/OTA first and only commit expense propotionate to its capabilities. I think that advice is sensible whether buying cameras, eyepieces or similar. How many of us have boxes full of redundant kit such as 1.25" eyepieces and filters when we are now requiring 2"?

I too think the AS1224 was a good choice considering the factors.

So what's new - it can and is be a dam expensive hobby - my input was just to give the person a wider view on equipment  in the relative area he was suggesting and the sort of images he could expect.  You were right to point out that the Hyperstar is not transferable but it looks to hold its value quite well.

[Howie_Oz]

Yeah mate ... have a crack with the 224 + reducer. Been there done that! LOL. Its still mighty powerful mag/narrow FOV with a 0.5x on the 1500mm FL 6SE tube though. So you'll be very limited to short exposures and any aberations in the tracking and bad goto's will show up. But it's all about having a go and learning and finding out. And cheap first go for you cos you already have the 6SE. Couple of tips ... I found the GSO 0.5x reducer to be rubbish. Second hand Mallincam reducers work really nicely. Much sharper views and less coma. Its tough to find them 2nd hand though (they are expensive (!!!) brand new). Plus you can double stack reducers with the very small sensor size of the 224 ... it handles it quite well. Secondly, if you do find it still has too much mag/narrow FOV/hard to goto, hard to track, hard to go long enough exposures, blurry stars .... its more the OTA problem with it still simply having too much FL/mag rather than a prob with the 224. Try to borrow an Orion ST80 from someone (although 2nd hand they are cheap as chips) and put it into the dovetail "clamp" on the 6SE mount. Much wider FOV/less mag so more forgiving on tracking, goto accuracy, field rotation with the small chip 224, much 'sharper' stars .... but you'll have to use a yellow #8 or #12 to cure the achromatic color fringing with it. The thing with the little ST80 mounted in the 6SE mounts dovetail clamp is that it makes a GREAT grab n go! Leave the thing all setup with camera the whole lot ready to go. You really dont have to use the tripod with the 6SE as the base has rubberised 'bits' underneath so you can plonk it on a car, the ground, a couple of bricks ... single cable from the cam to your laptop with you sitting in a chair and away you go. Bit tough to crouch and do all star alignment ... but get a 2nd hand StarSense and then you're really talking ... plonk it down, turn it on and in the couple of minutes the StarSense is doing your alignment you're getting the comfy chair and laptop out. By the time you're ready with that you're ready to start 'observing' with the 224. As they say the best scope is the one you use the most. And the easier the setup when we occaisionally see clear sky, the more we'll get out there ... and the more we can forgive the still fairly blocky/grainy/star bloat images coming from the 224 compared to other cams. But those other cams have their compromises ... longer exp time, etc. So crack on, cant wait to see how you go. 

[Todd1561]

Hey looks like this thread finally took off. Thanks for the the input everyone.  I did wind up ordering the 224 and a GSO 0.5x FR (before I read howies comment). It seemed to have decent reviews and I wasn't able to find anything else. I'll keep my eye on the 2nd hand market for a mallincam.  Were you referring to their standard 0.5x 1.25" FR that's only about $50 retail or the much more expensive MFR 5 II?  I'll definitely report back with how it goes. 

[roelb]

To give you an idea what the 6 SE is capable of, see: https://www.cloudynights.com/topic/585815-a-25-hour-session-with-6-se-asi290mm/

[Howie_Oz]

You got the 0.5x1.25" ... no worries ... just get out and use it and have fun experimenting! 

Those Mallincam (and other brands) 0.5x 1-1/4" and 0.5x 2" reducers are (IMO) all GSO's or that design spec, rebranded. They're all priced simiilarly, look identical, and have the same specs. I've tried several 2" out in field with the local astro club as many guys buy them and I've always found them blurry compared to the old Mallincam ones. But ... I see Roel's post above he was using the MFR5 ... he may have compared his MFR5 to the typical 0.5x cheap reducers and have a comment. IE dont just assume my findings on the 0.5 cheap reducers were the norm ... maybe the three or four I've tried were all rubbish offloaded to Aussie vendors at some point (LOL). Roel might have gotten a good one and reckon they're fine. You might have gotten a good one and find it great... so no probs keep it for now and get out and have a crack and see how it goes.

But, it was the MFR5 I was referring to. Comes with spacers and two lens units. Using those in different combinations of lens and spacers you can achieve a variety of reduction to suit diff targets. I got it with my Mallincam VSS+ which was my first venture into VA waaaaay back 6 or 7 years ago! Anyway ... the ZWO cam's come with a 1-1/4" adapter which screws onto the camera body. Into the 1-1/4" hole in that adapter you normally thread the ZWO 1-1/4" nosepiece. But if you end up finding a MFR5 2nd hand and buy it to give it a try ... you'll find you can thread the MFR5 into that 1-1/4" hole effectively replacing the need for a nosepiece and away you go.

 

[curtisca17]

Todd,

The ASI224 is a good camera to get started with as others have confirmed.  Works quite well when paired with Sharpcap SW which will allow you to stack images on the fly and extend the overall exposure to many minutes without star trailing.   I am glad to see that you also bought a 0.5X FR as that will help speed up your system and allow much shorter exposures which is critical with an Alt-Az mount.  As for the 6SE, I think given your desire to test the waters, it is a fine choice.  I wrote about it here:  https://www.cloudynights.com/topic/540494-light-weight-portable-low-cost-eaa-setup/  And you can find more images taken with the ASI224MC and 6SE on my web site here:  https://www.californiaskys.com/

Obviously one can put together a much better, and more expensive, EAA rig than the 224 + 6SE, but I can heartily recommend it for anyone looking for a relatively low cost, light weight, portable and easy to set up system.   You do not have to polar align since it is an Alt-Az mount, but Sharpcap will counter field rotation very well for, in my case, at least 5 minutes.  If you like EAA you can always move up in class.  If you want to stay with Alt-Az you can get a Nexstar Evolution which will track better than the SE or you can get an EQ mount if you really want to go to long single frame exposures.  I like my Hyperstar immensely but I think I would use it on a larger optical tube like an 8" or larger.  I can second the suggestion of the MC MFR5 II which is more versatile and I think gives better results than the much cheaper 0.5X reducers.  However, it is quite expensive and I am only able to get down to ~ f/4.5 without serious vignetting.

 

Good luck with your entry into EAA.

Best Regards,

Curtis

[Todd1561]

Excellent information everyone. I was going to head out tonight and use the new setup for the first time but clouds have been rolling in. Maybe tomorrow. In the meantime I've been trying the familiarize myself with SharpCap as I think the software alone will have a steep a learning curve as the gear/optics. Hopefully that will mean less fumbling around in the dark. I was looking for intro tutorial videos on using SC for EAA/stacking and came across this one. But it seems a little more geared toward video cameras, not USB. But maybe that's not critical, probably just setting the gain and whatnot is different. If anyone knows of a better resource I'd be happy to take a look. 

Thanks again everyone!

 

[Todd1561]

Btw, roelb and Curtis, excellent pics!  It's nice to know what I should expect to see after a lot of practice. 

[curtisca17]

Todd

 

I'm sure you can do much better than what i share.   Check this guide for some helpful insights on live stacking which does use USB cameras, although the process is not fundamentally different.   https://www.cloudynights.com/topic/596760-unofficial-sharpcap-quick-start-guide/page-2?hl=%2Bsharpcap+%2Bunofficial+%2Bguide#entry8399976

 

Regards

Curtis

[Todd1561]

I got out for a few hours last night and stuck with an easier target, M42, see attached. I think it's OK for a first attempt. I followed that guide, it was a great help. I'm surprised I was able to get as much as I did in my field of view with such a small sensor. I'm pushing that 0.5x focal reducer a little further than spec, but I haven't measured the actual reduction. 

I played around a lot with the settings. This was the best result and according to the sharpcap exported settings file I shot 182 frames at about 1/3s exposure and a gain of 475. I didn't do any darks/flats, I'll venture into that next time.  I doubt stacking that many frames added much benefit, the improvements seemed to taper off much before that.

My biggest issue was just finding targets,  my alignment wasn't great so I was doing a lot of hunting.  I bumped the scope after alignment and should have realigned but didn't.

If anyone has any suggestions for improvement I'm all ears. 

[shirva]

Easy,, relax and enjoy,,, it works its way out in the end lol,,,

Great first image

[Howie_Oz]

You've done well as that's about what we all see on our first goes. Good job mate.

Re number to stack ... you've already seen it and will now have in your mind what kind of number to stack yields a good result. Cos there's all sorts of recipes re what number is best. It is indeed a law of diminishing returns and sometimes stacking more than optimum leads to blurry images as more gear/motor pulse problems appear in more frames. Its a "give it go some night on one object" sort of thing for you to try out. Stack the equivalent of 1 minute (say thats 12 x 5sec frames), then 2 minutes (24 x 5 sec) then 4 then 6 then 8 and so on and watch for the difference in ease to move the sliders around to see the best you can get it, which both helps you learn what slider does what as well as the aha moments of Gee bright nebulas works best with about 5 minutes worth of total exposure time, but the dim stuff really needs 10 minutes, and star clusters only need 1 minute. Or something like that.

Re cannot find the objects .... the 6SE Nexstar hand control has a Precise GoTo menu item. Go look that up in the manual, and if you dont have the manual look for copy of the manual on the web or from celestrons website or an astro shops website. Basically if you cannot 'see' it then use the HC menu to initiate the Precise GoTo. It knows the constellation of your desired object and so knows the brightest star in that constellation and slews over to it. Being a bright star you can see it thru your finder! Tada! ... so move the scope using the arrow buttons to centre that star thru both the finder and then the camera (which again being bright star it WILL show it on the laptop). Once centered you press Enter and the HC works out how much the error in slewing to that bright star was in that constellation and so refines the accuracy of all targets in that constellation based on that error. So then you slew back to your desired object and its accuracy to land on the small sensor should be much better now.

 

cheers

[noah4x4]

Looks like my first effort with a DSLR. Excellent! I was delighted too. 

To improve clarity of detail, you probably need either longer exposures; which needs a wedge or GEM to avoid star trails; or if you continue with short exposures and stacking you would benefit from Hyperstar. But then it is back to the conundrum described in my earlier post. It is probably not worth investing in either whilst limited by a SE6.  So just enjoy where you are and when you do want to go to another level then budget carefully. Don't go spending money on stuff that isn't upgradeable (like Hyperstar for a 6" OTA).

 

 

[mboothe]

I think something like the Revolution Imager is a great match for the se6.