Finderguider adaptor from Modern Astronomy

[adamsp123]

I got one of these from Bern at MA - "Guide Camera Adapters for Finders", for what it is it is it seems a bit pricey but.... it works darn well, screw it in the Finder till it won't go any further, screw in the QHY5, the whole thing is rock solid and the camera chip is collimated nicely, much better shape to the stars than my original DIY version.

Tried and tested the last couple of nights, working better than my old version, been running 8 minute subs for hours and all frames were tidy.

Yep - recommend it if you got the dosh.

[The Sailor]

Any link to this please, tried Googling but nothing .

Jim

Opps, sorry, it's all in the thread name lol

[adamsp123]

link - http://www.modernastronomy.com/accessories.html

first item.

[AndyUK]

Yes, I bought one of these too - I haven't used it in anger yet, but as you say, quite expensive for what it is, but as a) I couldn't make one and I didn't want to order one from Canada for $40CAN + postage and then wait 4 weeks, this seemed like a good option...

[simon84]

Hi Pete, thanks for the information regarding the adapter. I'm looking for one to fit my QHY5 to a second guide scope for my portable widefield rig, was wondering if you can check something for me, the thread I have on the guide scope is 30mm and my QHY5 has two female threads on it but I cant measure these at the moment as I cant get my QHY5 off of the other guide scope. Will this adapter be suitable for the 30mm thread that I have?

Or do I remove the end cap from the tube completely and screw this adaptor directly into the guide scopes tube which has an internal thread of 53mm?

[adamsp123]

The ID of the synta finder I have is 50mm the OD 53mm, for that finder you unscrew the EP bit and discard, then the adaptor screws into the resultant opening.

Give Bern a call if you are unsure.

The smaller thread of the adaptor screws into the QHY5 nose piece thread.

HTH

[simon84]

Cheers Pete, this finder is slightly larger than a Synta finder, I have a synta finder/guider here and I took the back off hoping it would fit the new finder but its too small by at least 2mm. I cant check the size of the thread where that adpater goes on my synta finder because its all been glued in place.

Its looking like I will need an adapter that goes from 31mm male thread to T or C male thread. Might be a job for someone with a lathe....

[MikeWilson]

What finders are you guys using? I'm looking for a guiding solution now and a finderguider looks ideal (saving weight & money) compared to a guidescope, rings and mount...

[AndyUK]

Hi Mike - I have a spare Skywatcher 8x50 which I picked up for £20 from Astroboot. I think it's got an effective focal length with the Synguider of roughly 200mm (which might be a bit low?)

The back unscrews to reveal the thread that the adapter screws into, and the guide cam screws into the other side...

[MikeWilson]

Hi Andy,

Interesting! I hope it works out well for you.

I've just seen this on Astroboot that might accept a guide cam directly...

"A2 has a few scuffs on tube but all optics A1. Big Eye 10 x 50mm wide angle finder. Superb quality optics. 1.25" eyepiece fitting. Cross-hair eyepiece included (can be used in any 1.25" EP holder)" - £29.

What do you reckon?

[Deneb]

you'll have to use something like an empty barlow tube in addition to achieve focus with a guide camera like a QHY5.

Nadeem.

[MikeWilson]

Thanks Nadeem.

I'm thinking of getting a Synguider or LVI standalone autoguider to work with it.

This finder mounted in these rings (ScopeTeknix Universal 50mm finder bracket for all telescopes), maybe with a 1.25" extension tube to achieve focus.

I think that might be the ultimate small, lightweight and portable guiding solution for portable astrophotography...

[Deneb]

BTW i've done my 1st guided image :D:D

Why don't you try unguiding imaging for a while, lets see how much you can hack it

Nadeem..

[MikeWilson]

You're guiding now, eh? What made you change your mind?

And re: unguided imaging, I really want to get longer exposures. I've had 2 minutes 15 seconds on a VERY good day, but usually 60-90 seconds is as much as I can get away with.

I think pursuing guiding is a priority for me over modifying the camera itself.

[Deneb]

A friend of mine plunked his qhy5 on a diy 60mm guidescope he built me, i was quite surprised how easy it was after me doing unguided work for so long, he did not have to tweak it, as MartinB says it's good practice before you guide...

Now the Fun starts, now I want to play as well :evil6:

Nadeem.

[MikeWilson]

Well, let it be known that you are the master of unguided imaging - and - I'm not going to take that crown away from you Too much of a headache!

I understand that the LVI SmartGuider camera has a QHY5 at it's core and thus might be a nice option for combining with a DIY finder-guider.

My only issue now is finding a suitable mount that works with the Synta finder shoe bracket....

[adamsp123]

Mike, I got one of those finders from astroboot and was completely unimpressed by it, could not get it into focus with the EP/diagonal provided and doing visual checks the standard straight through synta finder is better optically IMO ie I wasted £29 but....that little scopeteknix finder bracket for £10 is super, I changed the plastic screws for metal ones adapted a dovetail bar to take it and put the dovetail across the top of my scope rings.

pic here http://stargazerslounge.com/members-equipment-gallery/116529-my-190mn-imaging-rig.html

[MikeWilson]

Interesting - you've just stopped me clicking on the order button.

What finder are you using? A 10x50 straight through Skywatcher finder? Also I'm not sure what bracket you mean. I've just found a quickrelease bracket for £15 that will fit in the Synta finder quickrelease shoe, however it's probably not suitable for guiding. I may get it anyway and custom drill some holes into it.

[adamsp123]

Interesting - you've just stopped me clicking on the order button.

What finder are you using? A 10x50 straight through Skywatcher finder? Also I'm not sure what bracket you mean. I've just found a quickrelease bracket for £15 that will fit in the Synta finder quickrelease shoe, however it's probably not suitable for guiding. I may get it anyway and custom drill some holes into it.

The bracket the one you mention ScopeTeknix Universal 50mm finder bracket for all telescopes

Hence the use though of the dovetail, I didn't want to modify my 190MN, would happily used the base as is on a Newt.

I have used the standard Synta (skywatcher) finder bracket but unmodified with the spring and rubber ring it is useless as you get mucho flexture, I did drill and tap one and added 6 metal screws, it worked fine but looked unsightly and at £10 that scopeteknix one is a real bargain IMO.

[MikeWilson]

The bracket the one you mention ScopeTeknix Universal 50mm finder bracket for all telescopes

Hence the use though of the dovetail, I didn't want to modify my 190MN, would happily used the base as is on a Newt.

I have used the standard Synta (skywatcher) finder bracket but unmodified with the spring and rubber ring it is useless as you get mucho flexture, I did drill and tap one and added 6 metal screws, it worked fine but looked unsightly and at £10 that scopeteknix one is a real bargain IMO.

Thanks for the heads up there. I'm thinking of getting the Skywatcher 9 x 50mm straight through finderscope (with the standard Synta finder bracket) and tapping the bracket in four places (replacing the two sprung parts with screws and adding an extra two holes for a total of four new screws). It's a great idea and I think it would work well.

Are you sure the mount is a £10 bargain? I see a £23.99 price tag

[AndyUK]

Hi Mike - I'm going to post a new thread about the synguider through a finderguider, as of course this is really about the finderguider adaptor...

It's extremely possible that I'm doing something wrong, but my first attempts seem to be showing that whilst focus was a little tricky to set up (as expected, and I'm still not 100% sure that I've actually got the best focus), I was having to use the maximum 4s to get a "brightness" over the recommended minimum of 10 units, and despite the fact that the guidecam locked onto the star (c. magnitude 3.5) the resultant images weren't exactly what I was hoping for.

Again, I'm hoping it's me, but maybe others will give me some tips on that thread - To make focusing easier though, there's always the option of getting a right-angle finder into which you can fit an eyepiece, and then you can use a parfocal ring and attach the guidecam via its nosepiece (which would of course actually make the finderguider adaptor redundant!), but at the moment I'm not totally convinced that a finderscope is quite powerful enough, and I may have to look into the dual mount and guide rings for my ST102

EDIT: [sIGH] Just realised that I hadn't reset the scope balance after adding the camera - No wonder the RA agressiveness was off the scale! Unfortunately battery pack is now all-but defunct so will have to wait another clear night...

[MikeWilson]

Hi Mike - I'm going to post a new thread about the synguider through a finderguider, as of course this is really about the finderguider adaptor...

It's extremely possible that I'm doing something wrong, but my first attempts seem to be showing that whilst focus was a little tricky to set up (as expected, and I'm still not 100% sure that I've actually got the best focus), I was having to use the maximum 4s to get a "brightness" over the recommended minimum of 10 units, and despite the fact that the guidecam locked onto the star (c. magnitude 3.5) the resultant images weren't exactly what I was hoping for.

Again, I'm hoping it's me, but maybe others will give me some tips on that thread - To make focusing easier though, there's always the option of getting a right-angle finder into which you can fit an eyepiece, and then you can use a parfocal ring and attach the guidecam via its nosepiece (which would of course actually make the finderguider adaptor redundant!), but at the moment I'm not totally convinced that a finderscope is quite powerful enough, and I may have to look into the dual mount and guide rings for my ST102

EDIT: [sIGH] Just realised that I hadn't reset the scope balance after adding the camera - No wonder the RA agressiveness was off the scale! Unfortunately battery pack is now all-but defunct so will have to wait another clear night...

How heavy was the camera if it really sent your balance off the scale? I have found that I need to leave my rig unbalanced (weights on the east side heavier than the OTA) to force the gears to work against the weights, else I get wierd dotted stars.

Looking forward to seeing how you get on, and I'll keep an eye out for your new thread (I might start one soon enough just as soon as I've figured out the pros and cons of the two auto guiders and the finder vs. ST80)...

[AndyUK]

Hi Mike - Yes, I try to do the same, but unfortunately it was the other axis... The camera (40D) weighs c. 700gms and I therefore have to shift the OTA forward by about 3".

I'm going to process the few images I did get (no darks etc), but the rejects had a LOT of trailing (which I'm going to put down (and hope is due) to poor the balance).

My first thoughts are that things would have been improved with being able to put a barlow in the path as that would have increased the brightness of the star image and therefore have enabled a smaller exposure (maybe 1s or less?)

[adamsp123]

I might have got that bracket from astroboot at some silly price, I will need to check, but even at £24 thats not too bad, have a look at the Celestron one!

Never had a problem getting guide stars with the finderscope

[riklaunim]

I'm looking at that hack for a finder to guide on planets when doing long exposures on them (methane band on Uranus etc.) but will it work with non-QHY5 cameras?

For DSO imaging at ~2000 mm Celestron OAG works nicely. Tried also with 80/400 refractor, but it didn't track well as the piggyback was shaking easily + extra weight.