guider using a philips spc880nc flashed to spc900 ???

[Les R]

Is one of these suitable to be used as a guider? I appreciate its not going to be the best, but is it worthwhile buying one cheap enough?

There is one on ABS at the mo...

[Mike]

It would certainly work on a large enough aperture guide scope. You could use it for planetary imaging too.

[Les R]

Cheers Mike. I had already offered the guy full asking within minutes of him posting but I thought astrobuysell is down. I hadnt heard back then spotted Id not got a confirmation either. I "reported" the item as I knew there was a problem as I did it a second time. Turns out, yahoo (his email address is sky and routed via yahoo??) has problems.

Anyway, have spoken to the guy and cam is now bought and paid for and comes with the adapter for £35 delivered.

http://www.astrobuysell.com/uk/propview.php?view=73552

[Les R]

The cam arrived ok. I removed the lens and screwed in the adapter. So far so good. But after removing the eye piece on the skywatcher finder on the 80ED, it's a slightly different size so doesn't fit!

I did buy a 9x50 Celestron which I fitted to the 6SE, so will check if the fittings are different. ( I'm sure it looks exactly the same!)

Anyone know what the adapter is called?  Obviously these adapters are not universal.

[The Thing]

These adapters are standard to fit 1.25 inch eyepiece holders, mind you I've also got a 2 inch one with a T thread... so it should fit.

[Les R]

These adapters are standard to fit 1.25 inch eyepiece holders, mind you I've also got a 2 inch one with a T thread... so it should fit.

In the finder, it has a screw in eye piece. The adapter I have is as you describe. The hole once the finder eyepiece is removed is nigh identical but obviously no good as its for a screw fit not able to hold something slid in.

[The Thing]

The eyepieces on finders are not interchangeable as a rule. You need a finder adapter to replace the whole back section

e.g. http://www.modernastronomy.com/accessories.html#accAdapters or
http://www.rothervalleyoptics.co.uk/t-thread-mount-adaptor-for-straight-finderscopes_d5246.html though they are t-thread adapters.

This guy used a bit he already had to adapt his finder http://buckeyestargazer.net/FinderGuider.html

Hope that helps.

[Mike]

Webcams are usually put into scopes such as the ST80 to use as guiders. For a small finderscope it is unlikely you would have enough aperture for an webcam which isn't particularly sensitive. You would have a lot of trouble finding guide stars with that setup I think. It's hard enough with a sensitive camera like the SX Superstar that I have. Either get a dual mount bar and an ST80 (or similar) and use that or get a dedicated guiding camera and use the webcam for planetary.

[MarkS]

Whats the focal length of a finderscope?

[Mike]

Mine is 225mm
F3.75

[Carole]

Les, what adapter are you using on the Webcam?  
Is it the the normal telescope adapter for imaging which is designed to fit a 1.25 nosepiece.?  

The adapter for the finderscope is one specifically designed for the purpose and to fit that particular camera.  
Bern could advise you.

Carole

[Les R]

Ok cheers guy. After watching a couple of the you tube videos on converting these finder scopes a while ago, I guess I rather foolishly believed they were suitable and worked!

Back to the drawing board then!

Actually, the WO66 that "got run over" should be suitable or is the field too wide on that also? I finally found out what the problem he was trying to describe was. What he was saying was that the telescope foot can't be rotated, so the focuser might not sit horizontal and the diagonal would need to be adjusted to suit your head position. Ie the OTA is what doesn't rotate. Everything else including the focusing works fine. He just described the problem poorly (like I probably just did too!) 

So would a WO66 be ok to use with a Philips 900 cam?

[Les R]

Whats the focal length of a finderscope?

On my way to work ATM. I will look to see if there is anything on it, but it is the standard finder that comes with the skywatcher 80ED.

Les, what adapter are you using on the Webcam? 
Is it the the normal telescope adapter for imaging which is designed to fit a 1.25 nosepiece.? 

The adapter for the finderscope is one specifically designed for the purpose and to fit that particular camera. 
Bern could advise you.

Carole

The adapter I was supplied with fits the cam fine. It would fit into a telescope in the same way an eye piece would. The problem here with the finder, is the eye piece actually screws in so what I have wouldn't work. The adapter that was posted above would work to get it connected, but now a mute point if it's not suitable. Is it a ST80 you use? I could have sworn you used something similar, but on reflection, I think my memory is playing tricks and you do use a ST80.

[Carole]

OK Les, it seems now if you're buying the W066 that you will have two scopes, so you don't need to use a finder guider, you can just insert the Phillips webcam into whichever scope you want to use as a guide scope.  You will have to find a way of mounting the two scopes so they are looking in the same direction and there is no flexure between the two.

I have some reservations with the Phillips webcam as a guider.  It does work, but it's not particularly sensitive compared to other guide cameras and you could find yourself hunting for a suitable guide star.  In which case you may have to use guide rings to manipulate the direction of the guide scope to find one.

There are a number of options here.  
You can mount piggy back, or side by side.
If you use the Phillips cam, I'd suggest either guide rings you can adjust, or the skywatcher guidescope mount:
https://www.google.co.uk/search?q=skywatcher+guidescope+mount&tbm=isch&tbo=u&source=univ&sa=X&ei=UepDUq25H8eJ7AawjoGQAw&sqi=2&ved=0CEMQsAQ&biw=1024&bih=605&dpr=1

You'll also need a GPUSB or Hitech guider to make the Phillips webcam work as a guider.  (I have the latter for sale if you were interested).  Not sure whether you could use this camera for pulse guiding as I have never done pulse guiding, those who have can advise.

HTH

Carole

[The Thing]

You'll also need a GPUSB or Hitech guider to make the Phillips webcam work as a guider.  (I have the latter for sale if you were interested).  Not sure whether you could use this camera for pulse guiding as I have never done pulse guiding, those who have can advise.

You can use any camera that provides a video stream for pulse guiding. It's far simpler than having extra cables and gadgets.

[MarkS]

I agree with Carole.  If you use a webcam as a guide cam then you will definitely need guide rings so you adjust the direction of the guidescope to find a bright enough guide star.  Something like the QHY5 is far more usable  as a guidecam and (I am told) the Lodestar is the ultimate.  A webcam modded for long exposures also works much better than a standard webcam giving a pecking order like this;

Webcam - bad but just about usable
LX modded webcam - pretty good
LX modded and monochrome CCD webcam - good
QHY5 - better
Lodestar - best

I've been recently using a standard webcam again, to do some periodic error tests (PERecorder only works with webcams).  It brought back all those (pre QHY5) memories of the pain of trying to find a guidestar!

[Carole]

Lodestar is the most expensive of these options, but I had a bad experience with one in France where Olly told me the cables did not provide a good connection and intimated that this was a general problem with Lodestars.  Because of this we had to abandon it in the end and use a QHY5 which is what many people swear by and it's a fair bit cheaper than the Lodestar.  Robert uses the latter and can provide more info on this.

You can still use the Phillips webcam for planetary imaging if you decide to get a different guide camera. 

BTW I used to use a modified webcam and it did work, but after some guiding problems where I was not sure what the problem was - Mark recommended I buy a QHY5 and I have to say this revolutionised my guiding. 

Carole

[Les R]

Hmmm.... So the Philips 990 isn't any good to use then? That was the reason I posted the thread, so I didn't buy something not fit for purpose. I already have a 5MP imaging cam (NexImage5).

On the skywatcher rings, there are two camera type screw threads. Is that where rings would be attached.

[mickw]

It is fit for purpose although not great and needs to be used with something with more aperture than a finder scope.

[MarkS]

The Philips 990 will definitely work and will give good results but it is not always easy to find guide stars.  Most of us started out with a webcam as our first guide camera because it's cheap way to start guiding. However, depending on the distribution of stars in the vicinity of your imaging, sometimes you'll find a suitable star straight way and at other times you can  spend 10 minutes of frustration trying to locate one - that's why you need plenty of adjustment on the guidescope.  On the other hand, with a QHY5 you will almost always find one straight away but that comes with a much higher initial cost.

As with most things in astro-imaging there is no single correct way to do things and everyone tends to take a slightly different approach depending on many different factors - expense often being a major consideration.

[The Thing]

On the skywatcher rings, there are two camera type screw threads. Is that where rings would be attached.

Les, there are two types of rings. Tube rings go round the imaging scope and fit tight around the tube. Pairs of guidescope rings have three screw adjusters around each ring so you can adjust where it points to pick up guide stars or align it with the imaging scope to use as a finder as well as a guidescope. (you probably know this).

The camera tripod bush type threads are for mounting cameras (suprise suprise) but you could also use them to piggyback a guide scope. If you use a piggyback arrangement, especially if you end up using a bigger guidescope, the effective weight  on the end of the scope goes up and you need far more counterweight. Side by side mounting mitigates this. Also the big thing you have to watch out for is flexure between the scopes which can vary at different angles as stresses and load vectors change during an imaging session. This will give you funny shaped stars on your images. Everything has to be very rigid to counter this.

However the most important thing is to assemble what you have got into an arrangement that will work to a point and try it out! Get out there and take some pictures. There is no substitute for practical trial and error and the new moon is approaching (again). That's how we all got going 

HTH and good luck

Duncan

[Les R]

Ok, cheers again guys.

I will give it a go using the cam and WO66 with a side by side mount. (I bought one a while ago) there doesn't seem much point shelling out on another adapter to get the 9x50 to work if it's likely I will run into problems. That said, I'd need rings to do this anyway?

Carole, isn't yours connected using the connectors on the two camera mounts on your 80ED?

All being well, I am picking up the WO66 on the 19 October..... As long as it doesn't look like it has been run over!