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Narrowband

Upgrading observatory imaging scope (SW ED80) to .... ?


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Hi everybody.

I have been imaging remotely & unattended for approx 1.5 years now, and the little ED80 has served me very well sitting with its Starwars style H-Wing i built to handle all the other equipment.

but...... 

IMG_1372.thumb.JPG.122cd0504c05c53ffa3bdc5d3d1327e0.JPG

... i only have a moderate amount of clear sky time (located in poland), but have a very nice dark sky i would like to use to the fullest. I am mainly focused now on narrowband & mosaics, whereby RGB will become a focus in the near future.

I'd like to optimize how much data i can gather. Currently i only see 2 ways, tandem-imaging with 2 scopes, or making the existing one faster.

The option of getting a second scope, filterwheel, camera, also concerning the software implications this will have, and also that probably i'm would stress the AZ-EQ6 too much, i think is currently not sensible.

The other option is to get signal faster, and also improve the signal (the ED80 has issues with reflexions, and aberrations). Looking towards more RGB, the ED80 will give me more fights than i'd like to have.

The requirements:

- I'd like to be able to make a scope upgrade that lets me keep my 1.25" baader lrgbhaoiiisii filters, as well as the 1.25" Atik EFW2 and the Atik 460ex, as well as the SharpSkyPro Focuser

- It should cope with the piggybacked ST80 and stay in similar weight conditions allover (or i will have to consider to go Off axis guiding, but not sure about that, will have to read more pro-con)

- it should be significantly faster, keeping the focal length somewhere close to 500

- it should have no CA or reflexion/halo issues and have crisp detail and a flat field

- It can be bigger aperture. I am currently thinking of 100mm

- Price wise i would not like to exceed 2000-3000$ but am flexible.

- I'd prefer a refractor, but am open to suggestions

 

As the ED80 is a common entry level scope, i guess a few of you have already been at this point, so would be happy to hear your suggestions and experiences

Update: The only scope until now that would meet all this criteria is the Esprit 100ED triplet being f5.5 with 550mm. It would be an F-Improvement from my 6.3 and also give me larger aperture. I haven't calculated it yet, but i suspect gathering signal should be approx 3 times faster?

Kind regards, Graem

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I won't be helpful, sorry, but I am curious, since you have said you are into narrowband, have you ever compared the ST80 to the ED80 in narrowband? I don't have identical aperture achromat and ED, otherwise I'd have tried it myself, so I am always wondering... ;)

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On 12/22/2016 at 13:38, ecuador said:

I won't be helpful, sorry, but I am curious, since you have said you are into narrowband, have you ever compared the ST80 to the ED80 in narrowband? I don't have identical aperture achromat and ED, otherwise I'd have tried it myself, so I am always wondering... ;)

As narrowband focuses on a very tiny spectrum of the light, CA isn't mostly a problem for the individual images, but for example the ED80 just doesn't have as sharp blue's as it does in other wavelengths so combining the images will always give you a challenge with the 'blue/purple fringing' that you have to sort out in postprocessing. I suspect it just being even worse with the ST80, and the ST80 has pinching problems (as the lense isn't attached as well as with the ED80). I only use the ST80 for guiding, and have never made a picture through it... sorry, can't help there :)

Kind regard, Graem

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Firstly allow me to stress I know very little to nothing about your type of imaging. I do however look around and may I suggest that if you want to go with a refractor you look at the Borg range sold by FLO, it will though take the thick end of your budget to acquire a 90mm F4 scope, I have seen them a touch faster but I would have thought that was about your limit.

It is a quality product and a fraction larger.

Alan

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1 hour ago, alan potts said:

Firstly allow me to stress I know very little to nothing about your type of imaging. I do however look around and may I suggest that if you want to go with a refractor you look at the Borg range sold by FLO, it will though take the thick end of your budget to acquire a 90mm F4 scope, I have seen them a touch faster but I would have thought that was about your limit.

It is a quality product and a fraction larger.

Alan

Thank you Alan, i'll have a look at those - only heard a few times about them, but always good.

I'm trying to figure out what my limitations are with the current 1.25" narrowband filters of baader (F-wise / Aperture wise?). Is going below F5 even realistic? I see that when you're closer to F2 you need special filters, but F2 with the kind of aperture i'm looking for is obviously not in the range i'm considering.

Kind regards, Graem

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I use F3.9 with 1.25" filters on a larger Kodak KAF8300 chip..... I don't see that will be a problem.....

What to do though? Here's a couple of rambling thoughts based on my own experience and not thinking about budget at all.... take from it what you will :)

I have an FSQ85 at f3.9 and decided that I wanted to get more data, quicker. So I went for a dual scope. My mount could take it, and so I decided to keep everything as simple as possible keeping the same FOV so another FSQ85 and another KAF8300 sensor. I saved money on the filters in that I decided to have a full set of filters in one camera (the one I already had) and in the second I've only put Luminance, Ha and OIII. I spent a lot of time drawing up scenarios of data capture and how the time would be best spent.

So it should be great.......... in a full night of imaging at say 10 hours, that's 20 hours of data :) Don't you believe it!!!

I've been struggling with the dual setup since August...... Flexure is your enemy ..... You can't use an OAG as if the OAG scope is focusing and the other is in the middle of a capture all hell breaks loose! I have taken it all apart in a huff and so far it's sat in bits on the obs floor. I take my hat off to those that get a dual setup working as it has totally eluded me so far. There's little software that runs dual setups either (so far I have found Prism and I think APT may do it now as well) 

At this juncture I would be loath to recommend dual based on my own experience. but people do get it to work and so I must just be a total numpty. Perhaps in the New Year when I give it another go, with a revised mounting system and scope rings I may feel differently.

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2 minutes ago, swag72 said:

I use F3.9 with 1.25" filters on a larger Kodak KAF8300 chip..... I don't see that will be a problem.....

What to do though? Here's a couple of rambling thoughts based on my own experience and not thinking about budget at all.... take from it what you will :)

I have an FSQ85 at f3.9 and decided that I wanted to get more data, quicker. So I went for a dual scope. My mount could take it, and so I decided to keep everything as simple as possible keeping the same FOV so another FSQ85 and another KAF8300 sensor. I saved money on the filters in that I decided to have a full set of filters in one camera (the one I already had) and in the second I've only put Luminance, Ha and OIII. I spent a lot of time drawing up scenarios of data capture and how the time would be best spent.

So it should be great.......... in a full night of imaging at say 10 hours, that's 20 hours of data :) Don't you believe it!!!

I've been struggling with the dual setup since August...... Flexure is your enemy ..... You can't use an OAG as if the OAG scope is focusing and the other is in the middle of a capture all hell breaks loose! I have taken it all apart in a huff and so far it's sat in bits on the obs floor. I take my hat off to those that get a dual setup working as it has totally eluded me so far. There's little software that runs dual setups either (so far I have found Prism and I think APT may do it now as well) 

At this juncture I would be loath to recommend dual based on my own experience. but people do get it to work and so I must just be a total numpty. Perhaps in the New Year when I give it another go, with a revised mounting system and scope rings I may feel differently.

Sara, thx for chipping in. 

My gut also tells me that going for dual is currently a too big of a step and i'll be biting off more than i can chew. Thats why i wanted to rather upgrade the scope first, and still having the ED80, maybe in future i can play around with dual.

I updated my original post: The only scope that seems to fit my (rather tight) requirements, is the Esprit 100ED. its reviews are good and it seems a good deal faster than my ED80. Furthermore i would not have to fight with the CA as i have to now.

I'm hoping somebody can still give me a few concrete scope hints as there must be people out there having started with the ED80 and stepped up successfully or failed (and i both cases i would like to know! :) )

Kind regards, Graem

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P.s. just still found the TSAPO100Q that fits the specs http://www.teleskop-express.de/shop/product_info.php/info/p6478_TS-Optics-100mm-f-5-8-Quadruplet-Astrograph---FPL-53-APO-Objective.html

Advantage seems to be the integrated field flattener as well that its a quadruplet. But i've not read too many reviews yet about it.

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I would think that the new WO Star 71 MkII would be worth a consideration..... with the excellent customer service from FLO, fear of a dud is a no brainer as you can easily return it if there's issues. Also these are checked prior to dispatch......

No flattener, no reducer = An easy life of no spacing :D 

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50 minutes ago, swag72 said:

I would think that the new WO Star 71 MkII would be worth a consideration..... with the excellent customer service from FLO, fear of a dud is a no brainer as you can easily return it if there's issues. Also these are checked prior to dispatch......

No flattener, no reducer = An easy life of no spacing :D 

Add a mount that doesn't need guiding and you have imaging heaven 

Be trying to fit dual rig after Christmas so probably all go pear shaped then :grin:

Dave

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1 hour ago, swag72 said:

I would think that the new WO Star 71 MkII would be worth a consideration..... with the excellent customer service from FLO, fear of a dud is a no brainer as you can easily return it if there's issues. Also these are checked prior to dispatch......

No flattener, no reducer = An easy life of no spacing :D 

Thx Sara for the suggestion. I have not considered going THAT widefield (rather would want to stay around 500, as i do really like that focal length, and still have easily 1-2 years of mosaics infront of me :p ) and furthermore: would that scope really be faster considering 9mm less aperture (even if F is higher) ?

39 minutes ago, Davey-T said:

Add a mount that doesn't need guiding and you have imaging heaven 

Be trying to fit dual rig after Christmas so probably all go pear shaped then :grin:

Dave

Good luck, please do share your experiences!

Concerning guiding: I must say i have never seen the issue with it, it just works and i guide at 0.6" constantly. But at these low focal lengths as i am using my guider could be drunk and stars would still be sharp :)

Also still found the STELLARVUE SVQ100, seems to be very well established as well in this category.

Do you think i'm making a mistake going for approx 100mm? I just see this as an 'easy' step to gathering signal faster as going much lower with F gets expensive fast. The weight of these scopes is considerably more than what i have now. My ED80 is 2.5kg vs the TS 100 or Esprit 100 being 5-6kg. But i think my AZEQ6 can still handle those 3 extra kilo..... the ST80 is a feather and the rest is standard (my frame is aluminium so very lightweight)

Kind regards, Graem

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If you're feeling brave

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7331_TS-Optics-Imaging-Star-102-mm-f-5-1---6-Element-Flatfield-Apo-Teleskop.html

Personally, after my experiences with their 80mm f/4.4 I would steer clear of their integrated reducer 'scopes. But if you want to have a punt it looks like it fits your bill.

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When I upgraded from my ED 80, I too went for a 100mm refractor, in my case the William Optics FLT 98, possibly the best refractor they ever made but, surprisingly, no longer manufactured but they do come up second hand. I don't have direct experience of the Esprit 100 but if it is as well made and delivers the same flat field (with optional field flattener) as the Esprit 150 that I do have, this would be a good choice.

I would steer clear of dual imaging for now - I have successfully used this method but there is plenty to go wrong too and AP is difficult enough without the extra complications!

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4 hours ago, DaveS said:

If you're feeling brave

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7331_TS-Optics-Imaging-Star-102-mm-f-5-1---6-Element-Flatfield-Apo-Teleskop.html

Personally, after my experiences with their 80mm f/4.4 I would steer clear of their integrated reducer 'scopes. But if you want to have a punt it looks like it fits your bill.

Thank you Dave. What bad experience did you have?

4 hours ago, steppenwolf said:

When I upgraded from my ED 80, I too went for a 100mm refractor, in my case the William Optics FLT 98, possibly the best refractor they ever made but, surprisingly, no longer manufactured but they do come up second hand. I don't have direct experience of the Esprit 100 but if it is as well made and delivers the same flat field (with optional field flattener) as the Esprit 150 that I do have, this would be a good choice.

I would steer clear of dual imaging for now - I have successfully used this method but there is plenty to go wrong too and AP is difficult enough without the extra complications!

My thoughts exactly (concerning dual imaging), its just a too big a step for me now - the implications in software and hardware would be too big.

I am very keen on the Esprit 100 the longer i research. No bad reviews yet.

Not sure yet how much the integrated flattener is really of an advantage. If its just about the spacing its not a huge selling factor, as you do that once. But as they state these integrated flatteners have been tested & spaced to perfection (if true or not to be disputed) and that you can not reach that kind of results with a screw-on-flattener.

Kind regards, Graem

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It wasn't just me having problems, ultranova bought one as well and he had the same runaround, trying to get the spacing right, the ones we bought were different to the photo on the site, as we had a rotator instead of the tilt adaptor, TS weren't very helpful regarding the spacing from the flattener flange, which is what we needed to calculate the new spacing. We also had loads of problems getting tilt out of the system. I think he managed to send his off to TS via Modern Astronomy but I bought mine direct and would have to sort out my own courier arrangements.

TBH I think the 102mm might not be so horrible as it's not as extreme, and has the spacing given from the rotator.

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