Fear of Space ... rs

[Joel Shepherd]

I'm the nervous new owner of a Skywatcher Esprit 80 ED APO, which I intend to pair up with an Atik 460ex. (No first light yet for the scope ... nor the next couple of weeks by the looks of it. Sigh.)

I understand why I need spacers between the field flattener and the camera, but I'm wondering how/where I obtain them. I can't believe that everyone who needs spacers has to wander over to their neighborhood machine shop to have something custom made. But browsing a few big astronomy suppliers here in the States (OPT, Highpoint, Orion), the variety of spacers offered is pretty meager.

What is the process for figuring out the exact spacers you need, and, maybe more importantly, how do you obtain them?

Thanks! -- Joel.

[Leveye]

If you want or need anything custom made and your in the States try PreciceParts for threaded metal ones. Astronomics,Agena astro and Scopestuff all carry spacer rings. There are now slim delrin spacer rings out there. I'll try to find them and link you. I think they are Blue Fireball.

[hjw]

Hi Joel,

if you have a field flattener already, you won't require a spacer. I can achieve focus with a flattener but not without. I started off with an extension tube but once I got the flattener this part was obsolete.

Cheers

HJ

[Waldemar]

Your ATIK has a backfocus of 13 mm, your SW field flattener has 55 mm. BF

so you will need 55-13 = 42 mm extra spacing. The Baader Varilock 46 offers a variable spacing from 29 to 46 mm. That should do the job and leaves you with plenty of possibilities to adjust to your needs.

A second, cheaper  option would be to buy a Baader 40 mm T2 spacer and a set of Delrin spacers.

Waldemar

[Dave In Vermont]

If I may repeat Leveye: ScopeStuff -

http://www.scopestuff.com/

And you can also call Jim there, if you don't see what you need, and ask him for a good source. He's a great guy. And pack a lunch before you visit the site. People have gotten lost in there!

Dave

[ollypenrice]

Hi Joel,

if you have a field flattener already, you won't require a spacer. I can achieve focus with a flattener but not without. I started off with an extension tube but once I got the flattener this part was obsolete.

Cheers

HJ

It's not about focus but about the correct spacing between between flattener and camera chip. Depending on the specific kit and, above all, the chip size this can require sub mm precision.

Olly

[Joel Shepherd]

Great: thanks for the leads. I'll start poking around.

In the interests of complicating things ... Suppose I have the flattener, appropriate spacers and a camera, and I want to insert a filter into the mix. Where in that assembly does the filter go? What effect does a filter have on spacing requirements?

As a follow-on to that, suppose I want to put a filter wheel in place. Do folks typically just leave that permanently attached to the camera, or is there ever need to change up configuration and change spacers between sessions?

Thanks! -- Joel.

[hjw]

Having shown my ignorance already I wager another input: I put the filter in front of the flattener.

At this point I would like to ask Olly how you determine the right distance between flattener and chip. I had never even considered the necessity... my pictures improved and I was happy. Maybe they could improve even more if I do it right.

Cheers

HJ