Skywatcher 2 inch adapter help

swannies1983 (Dan) · #1 22-10-2011, 03:43 PM

Right, this is getting rather annoying!

I have started some prime focus imaging using my 8" Newt. I was lucky in that I didn't have to buy a low profile focuser or move the primary mirror up to achieve focus (that's a relief). The reason is that the scope had an adapter similar to this one http://www.myastroshop.com.au/produc...sp?id=MAS-052H This gives me about 5-8mm of in focus remaining.

Now, I recently acquired a LPS filter. First problem: I said I have an adapter similar to the one above, but mine does not have a 2" filter to accommodate the LPS filter. Ok, no worries, I'll just buy the adapter as shown in the link. Wrong, it won't work. Why? Because the 2" skywatcher visual back is NOT 2 inches, so the Lumicon adapter in the link above is too small. I have become aware that to use 2" accessories, I have to buy a 2" adapter that drops in the drawtube. Second problem: This adapter raises the height of the focuser, preventing me from achieving focus with my DSLR.

So, what do I do? Has anyone experienced this same problem? If so, what have you done? I guess one option is to make the component that screws onto the drawtube, but make it with an ID of 2".

NOTE: Why the hell did skywatcher make a setup like this? What's the positive in having to buy a 2" adapter to use 2" accessories?? Ggggrrrr..

bmitchell82 (Brendan) · #2 22-10-2011, 05:21 PM

hehehe its good to see that sky watcher is still screwing people over!

it is a 2 inch focuser, but once you get into the tube its ever so slightly smaller to stop tihngs from flying into the tube.

Quick fix, get somebody to put the colloar to the draw tube into the lathe and mill out a very very small slice from the inside, this allows your 2" to slide right down.

More expensive fix, and more than likely one that you will do anyhow is buy a decent focuser Moonlight, Feather touch or the like

Good luck
Brendan

swannies1983 (Dan) · #3 22-10-2011, 05:36 PM

I'm not sure if that's the problem. A picture is best to explain. On the left, is what screws into the drawtube. The ID is ~57mm. The component on the right is the 2"-1.25" adapter. A 1.25" tube screws into this to allow the use of 1.25" eyepieces. However, when you unscrew this barrel, there's a T-mount thread which I use the attach the camera.

The component on the right is similar to the Lumicon one in the link I provided. The difference is that the Lumicon one has a 2" filter thread. The problem is that the Lumicon one is 2" and will be too SMALL to fit the the holder (left hand component in picture).

You can buy a 2" adapter that fits in the component on the left-hand side, but that increases the height of the focuser. No good for me.

So, can I buy the left hand component but with a 2" ID? I guess I could reduce the ID somehow....

bmitchell82 (Brendan) · #4 22-10-2011, 07:13 PM

if you havn't already purchased the 2" filter then look at the clip in filters this will get rid of your issue!

swannies1983 (Dan) · #5 23-10-2011, 08:57 AM

Too late, as I already have the filter. The jigsaw puzzle continues.

swannies1983 (Dan) · #6 23-10-2011, 10:43 AM

I actually came across this thread http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4108582/page/0/view/collapsed/sb/5/o/all/fpart/1 and one of the posters said this
"I believe the adapter is there because the focal point is further outside tube that focuser travel allows without a spacer. I removed the 2 inch adapter on a skywatcher scope, and replaced the collar on the focuser tube(screw on black piece with set screw) with one from an Orion crayford focuser that was actually 2 inch."

I'm interested in the bolded part and have asked the poster some questions. I think I can fix my problem if I can in fact get a collar that replaces mine, but has an ID of 2". Does anyone have an orion crayford focuser? If so, does the collar from this focuser screw into the original skywatcher drawtube? The skywatcher drawtube has an ID of ~2.25".

Tandum (Robin) · #7 23-10-2011, 10:58 AM

Dan, I believe jjj and RobF both had these issues with skywatcher newts. I'm not sure what jjj did and she is away at the moment, but RobF added a coma corrector which moves the focus point out of the scope. The baader mpcc is front threaded for a 48mm (2") filter and I see you can get a GSO branded one now for less money. The cheapest option though is to move the primary mirror up the tube as outlined in this article.

swannies1983 (Dan) · #8 23-10-2011, 11:05 AM

Yeah I understand I could use the MPCC but that would require me also getting a 2" adapter which slips into the drawtube. I don't want to buy a coma corrector at this stage given the price.

I will be in contact with jjj.

Thanks

swannies1983 (Dan) · #9 23-10-2011, 11:37 AM

aha! Looks like there's a better option. It just involves buying a 52mm-48mm stepper ring and simply aralditing to the backend of the 2"-1.25" eyepiece adapter (the component on the right hand side of the photo I attached)

See here http://astrochat.co.uk/forum/viewtopic.php?t=13530. Unfortunately the pics don't work but you get the idea.

Found a picture here http://stargazerslounge.com/1397576-post2.html

bmitchell82 (Brendan) · #10 23-10-2011, 03:26 PM

the cost of a MPCC isn't expensive at all and using the newt you will need one if you go to andrews and bintel its exorbinately priced I got mine from

http://www.tan14.com/Baader.htm

and alot of other people have delt with Peter Tan with great results

Talk toyou then