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RASA 8" filter drawer


Bigfoot 9907
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Greetings all, any RASA 8 owners out there?  I'm wondering what 2" filter drawer you are using. I know that back focus is important so i don't want to get the wrong one. I've seen a ZWO for £79 and a Starizona for £139.

Any recommendations would be great.

Cheers 

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I used the Starizona one with my RASA 8 and it was very good. There was no ZWO option when I bought it. If you go with ZWO make sure its exactly the same measurements as the RASA is extremely sensitive regarding distance to sensor, it needs to be exact. There is also an Artesky filter holder - but its not a draw system, just holds a single filter so probably better for OSC rather than mono. I've heard it is very good though and if I still had a RASA that's what I'd be using for my 2600MC. 

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p11535_Artesky-2--Filterhalter-und-T2-Adapter-fuer-Celestron-RASA8-Astrograph.html

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I started using the Baader filter draw system but found a draw back with it in that you couldn't mount the filters so the correct face faced the sky. Whether that would have made a difference I don't know but Baader filters are usually intended to be used in a given orientation. I think there amy be a new version out now.

I ended up making my own draw system to go with the ASi533 I use on the RASA 8. (Photo shows an ASi294 which I have now sold and replaced with the 533) both have the same back focus 6.5mm.

UFC_Repl-2.jpg

Edited by fwm891
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1 hour ago, ollypenrice said:

Whatever Gorann is using is what I'd use!

:Dlly

Because I only use OSC (ASI2600MC) with my RASA I use the Artesky adapter so that I can use a 2" IDAS NBX (NBZ) filter for dualband when the moon is out. I did use the Baader system initially and it seemed to work fine, at least with a Baader high-speed Ha filter.

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  • 3 weeks later...
On 19/06/2021 at 10:00, fwm891 said:

I started using the Baader filter draw system but found a draw back with it in that you couldn't mount the filters so the correct face faced the sky. Whether that would have made a difference I don't know but Baader filters are usually intended to be used in a given orientation. I think there amy be a new version out now.

I ended up making my own draw system to go with the ASi533 I use on the RASA 8. (Photo shows an ASi294 which I have now sold and replaced with the 533) both have the same back focus 6.5mm.

UFC_Repl-2.jpg

Nice filter adapter. Could you do a similar system for cooled cameras with a 17.5mm backfocus?

(I don't know what's the RASA backfocus spec)

N.F.

 

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A RASA8 has a back focus of 25mm when  measured from the M42 adapter or 28.7mm if measured from the reference surface (i.e. M42 adapter removed).

You should download the 'White Paper' from the Celestron web site, it gives all the specs and drawings for the RASA scopes.

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