Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Uranium235

First Light: WO Star71 (IC1396)

Recommended Posts

The conditions were not exactly favourable last night... full(ish) moon, a touch of high cloud - but I wasnt going to let that stop me from breaking in this new telescope!

First up was getting the balance right, so I mounted the finderguider as far forward as it can go. Second issue was finding a way to attach my RDF - no problem... a bit of wood with a finder shoe on it bolted to the top dovetail. The RDF weighs almost nothing, so wood will be fine for now. However, Ive since tightened up the guider fastenings since last night because I had a bit of flex when trying a 30min sub. 

So, a few observations on the Star 71:

Field flatness: Out of the box.... its great. I might tweak it a little (at the focuser), but I wont do that until I can be certain that my extensions/FW etc are 100% straight. There was a little dodgyness in one corner, but im not sure whether thats down to the way the FW is attaching to the focuser - the 71's M48 thread seems a bit "tight" (ie: nothing screws all the way on).

Vignetting: Over the 8300 chip.... ermmm what vignetting?!

Contrast: Cor blimey guv'nr, loads of it!  (histogram was well left, despite the moonlight)

Also, its surprisingly heavy for a small frac - and the focuser is probably the best ive ever used. I dont have a suited B-mask for it yet (was using my old 100/f6 mask), but I'll get one eventually for it. Another thing I'd like to try is converting it to a Canon bayonet connection so I can quick change cameras without having to dismantle everything. I've a feeling the 1000d would do very nicely on this too.

So far, the 71 has been given just 1/4 of the exposure I used on this target with the 130pds. I've calculated it should be roughly x2 faster than the 130 over the same area of sky.

14x900 (Ha)

WO Star 71, Atik 383, NEQ6

Thanks for looking :)

21702514306_6722b0aca9_h.jpg

Fullsize for pixel peepers and corner fanatics:

https://farm1.staticflickr.com/774/21702514306_bb19582e2b_o.jpg

  • Like 35

Share this post


Link to post
Share on other sites

Very helpful review, particularly as I'm seriously considering this scope myself (the whole refractor strategy/analysis is in the air !).  Still a top contender based on this.  I don't like the relatively short back focus, mainly because I'm an OAG obsessive - and it looks like only a new skinny one at best would fit.  But it would piggy-back fine on the C9.25.  Good to hear you like the focuser.

Share this post


Link to post
Share on other sites

Welcome to the club! I love this little scope.

Sent from my SM-G925F using Tapatalk

Share this post


Link to post
Share on other sites

Very helpful review, particularly as I'm seriously considering this scope myself (the whole refractor strategy/analysis is in the air !).  Still a top contender based on this.  I don't like the relatively short back focus, mainly because I'm an OAG obsessive - and it looks like only a new skinny one at best would fit.  But it would piggy-back fine on the C9.25.  Good to hear you like the focuser.

With the camera and FW attached I have about 27-28 of focus in-travel left so there may be just enough room if your OAG is under that.

Ive a feeling this will do rather well on the dark stuff, and definitely good in RGB - which i'd like to get round to because I didnt buy this just for great narrowband :)

  • Like 1

Share this post


Link to post
Share on other sites

Great image I get the impression that you quite like this scope.

Alan

Share this post


Link to post
Share on other sites

No flattener spacing to worry about, No vignetting, good focuser, fast and contrasty. Sounds like a dream scope! Enjoy :)

  • Like 1

Share this post


Link to post
Share on other sites

Great image and work !

Thanks for sharing.

Clear skies.

Share this post


Link to post
Share on other sites

Just found the source of last nights corner issue, its the 2" thread on my FW.

I tried some other 2" threaded items and they screwed all the way on with no fuss or tightness. So ive inserted a 10mm 2" extension between the focuser and the FW - which should hopefully make for a better connection.

Oh, while im here - a big thanks to FLO for getting the 71 to me so quickly... under 24 hours! (now thats fast!) :)

Share this post


Link to post
Share on other sites

lovely image there Rob and nice scope as well.

can you explain some thing to me  you say that the 71 should be 2x faster than the 130pds if the 71 is F4.9 and the 130 pds is F5 is the 0.1 that much of a difference or am i missing some thing . sorry if i am a bit dumb 

Share this post


Link to post
Share on other sites
toxic, on 26 Sept 2015 - 7:15 PM, said:

lovely image there Rob and nice scope as well.

can you explain some thing to me  you say that the 71 should be 2x faster than the 130pds if the 71 is F4.9 and the 130 pds is F5 is the 0.1 that much of a difference or am i missing some thing . sorry if i am a bit dumb 

No prob mate :) When I say it will be 2x faster, I mean that over a 4 pane mosaic with the 130 2x2 binned - the 71 will do it in just one pane in half of the (total) time unbinned. Actually, the 71 captures a slightly larger field and at a slightly better resolution than a binned 130, plus I no longer lose any pixels from cropping/overlapping of panes.

eg: IC1396

130pds: 4x3.5 hours (2x2 bin) = 13 hours

WO 71: 1x6 hours (1x1 bin) = 6 hours

If I were going for something smaller I would switch to the 130, hence the interest in bayonet adaptions - which would make switching around really simple. But for the moment there is enough big stuff to keep me going until January :)

  • Like 2

Share this post


Link to post
Share on other sites

Great image. Looks like you have a winner :)

Share this post


Link to post
Share on other sites

Fabulous. I'm ashamed to say that I clicked on the pixel-peepers' and corner fanatics' link ... and it looked great to me.  :grin:

This really does have to be a tempting scope.

Olly

  • Like 1

Share this post


Link to post
Share on other sites

Very helpful review, particularly as I'm seriously considering this scope myself (the whole refractor strategy/analysis is in the air !).  Still a top contender based on this.  I don't like the relatively short back focus, mainly because I'm an OAG obsessive - and it looks like only a new skinny one at best would fit.  But it would piggy-back fine on the C9.25.  Good to hear you like the focuser.

I'm also fond of OAG and have successfully used my Orion OAG with the Star71, which isn't the skinniest one around.  I only have to rack out the focus around half a centimetre so it just manages it.  I do have a 7.5mm extension in between the QHY8L and the OAG to assist in getting it parfocal with the guide camera so it will depend on what you have in your own OAG imaging train as to whether you'll have more latitude in your focus travel or not.

I've been very happy with my Star71 so far.  It provides a nice flat field across the APS-C sized chip of the QHY8L, giving big field views.  I also like the fact that I can screw the camera onto the scope which helps get everything orthogonal and rigid. 

Share this post


Link to post
Share on other sites

Oh my, that is one tasty first light and in less than optimal sky conditions. I am definitely a step closer to joining the club. The price tag is appealing too.

Love the framing of your chosen target too.

Share this post


Link to post
Share on other sites

Just had a look on FLO... WO 71 Status: 'Available - Delivery 20-25 working days.'... You caught a lucky stock day!

Share this post


Link to post
Share on other sites

Congrats on a great little scope Rob, lovely FL image, I've had one for a while now but been waiting for the autumn for serious imaging using QSI683, got it set up on a dual rig with WO110FLT and swap the guider and camera between them, don't think the 71 should need  OAG.

Bought the WO RDF but not that impressed with it, the illumination is too bright and the lines on projected reticles are too thick.

Dave

Share this post


Link to post
Share on other sites

Congrats on the new scope Rob, that's a great image despite the conditions. Like Olly I too looked at the corner stars and they look really clean and tight to me. I'm seriously considering getting one of these myself to compliment my FLT98.

Share this post


Link to post
Share on other sites

I'm also fond of OAG and have successfully used my Orion OAG with the Star71, which isn't the skinniest one around.  I only have to rack out the focus around half a centimetre so it just manages it.  I do have a 7.5mm extension in between the QHY8L and the OAG to assist in getting it parfocal with the guide camera so it will depend on what you have in your own OAG imaging train as to whether you'll have more latitude in your focus travel or not.

I've been very happy with my Star71 so far.  It provides a nice flat field across the APS-C sized chip of the QHY8L, giving big field views.  I also like the fact that I can screw the camera onto the scope which helps get everything orthogonal and rigid. 

I have the gigantic Celestron OAG, which you measure by walking round it and counting the paces !  Not a problem with the SCT but this is just another issue to get my head round as I enter refractor land....sometime.

Share this post


Link to post
Share on other sites

Congrats on the new scope Rob, that's a great image despite the conditions. Like Olly I too looked at the corner stars and they look really clean and tight to me. I'm seriously considering getting one of these myself to compliment my FLT98.

The corners are only looking clean in that image because the stacking and meridian flip averaged out the one dodgy corner. I've since had a look at it with the cheshire, and im sorry to report it looks like the cell collimation might be a little bit off (not getting concentric rings in the cheshire). The focuser is fine, it fired a collimating laser right out of the centre of the front objective no problem.

I'll take it out again tonight and simplify by using the DSLR, that will reveal the bigger picture - and eliminate the CCD as a cause if its still the same.

Share this post


Link to post
Share on other sites

No prob mate :) When I say it will be 2x faster, I mean that over a 4 pane mosaic with the 130 2x2 binned - the 71 will do it in just one pane in half of the (total) time unbinned. Actually, the 71 captures a slightly larger field and at a slightly better resolution than a binned 130, plus I no longer lose any pixels from cropping/overlapping of panes.

eg: IC1396

130pds: 4x3.5 hours (2x2 bin) = 13 hours

WO 71: 1x6 hours (1x1 bin) = 6 hours

If I were going for something smaller I would switch to the 130, hence the interest in bayonet adaptions - which would make switching around really simple. But for the moment there is enough big stuff to keep me going until January :)

Ahhhh the penny drops. thanks rob i forgot about the field of view !duh!   :shocked:  

Share this post


Link to post
Share on other sites

Congrats on a great little scope Rob, lovely FL image, I've had one for a while now but been waiting for the autumn for serious imaging using QSI683, got it set up on a dual rig with WO110FLT and swap the guider and camera between them, don't think the 71 should need  OAG.

Bought the WO RDF but not that impressed with it, the illumination is too bright and the lines on projected reticles are too thick.

Dave

I use the OAG on my Star71 out of convenience really.  I originally got the OAG for use with my 8" RC where it is essential and it's just easier for me to simply swap the OAG package between the scopes as required rather than set up some other guiding method for the Star71.

Share this post


Link to post
Share on other sites

The corners are only looking clean in that image because the stacking and meridian flip averaged out the one dodgy corner. I've since had a look at it with the cheshire, and im sorry to report it looks like the cell collimation might be a little bit off (not getting concentric rings in the cheshire). The focuser is fine, it fired a collimating laser right out of the centre of the front objective no problem.

I'll take it out again tonight and simplify by using the DSLR, that will reveal the bigger picture - and eliminate the CCD as a cause if its still the same.

Sorry to here about this Rob, just a thought would it be better to bang in a 3-5x barlow lens and rack focus intra & outro to check the diffraction rings are concentric using the old MK1 eyeball. also is it possible the built in flattener could be at fault I wonder if that is adjustable?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.