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RASA 8 f2 filters

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#1 arrowspace90

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Posted 06 December 2019 - 09:28 AM

Well, I hesitate to ask questions when I know so little but..

 

I have a RASA 8 on the way to be mounted on a EQ6-r.

I will have the ASI533 color camera.  Starizona filter drawer.

 

I am wondering, among unlimited issues that I am clueless about, what are the must have f2 filters that I will need to use to get started with the AP?

 

Specifically, do I need the Celestron light pollution filter to use in place of the clear filter window that comes on the RASA?  

Yes, I will be under Bortle 4 to Bortle 7 skies in the burbs.  Is there any reason to make this choice instead of a LPF that is not just for the RASA?

 

What other F2 filter, a hydrogen filter for example, will I need to have in that filter drawer?

 

Please answer, if you can, in your most simple language, as any "pro" terms and acronyms are likely to go right over my head.  If you have a RASA, what would you not leave home without?  Obviously, all these accessories are expensive.



#2 bobzeq25

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Posted 06 December 2019 - 11:17 AM

Simple is good.  It's all to easy to overcomplicate this, and overemphasize relatively minor improvements in equipment.

 

For emission nebulae (only), I like the Celestron filter.  I see no reason why another broadband LP filter would be better.

 

You can also do other kinds of imaging, but I see no _need_ for other filters.  _Particularly_ when you're starting out.  There's a ton of stuff to learn, best to concentrate on getting the basics down before going for Image of the Day.  <smile>

 

This activity is knowledge driven, and you'll never get enough from short posts here.  I recommend this book.  You won't understand all of it right away, but you'll understand more and more as you gather experience, and reread it.  My copy is well worn.

 

https://www.amazon.c...d/dp/0999470906


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#3 pyrasanth

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Posted 06 December 2019 - 11:52 AM

Simple is good.  It's all to easy to overcomplicate this, and overemphasize relatively minor improvements in equipment.

 

For emission nebulae (only), I like the Celestron filter.  I see no reason why another broadband LP filter would be better.

 

You can also do other kinds of imaging, but I see no _need_ for other filters.  _Particularly_ when you're starting out.  There's a ton of stuff to learn, best to concentrate on getting the basics down before going for Image of the Day.  <smile>

 

This activity is knowledge driven, and you'll never get enough from short posts here.  I recommend this book.  You won't understand all of it right away, but you'll understand more and more as you gather experience, and reread it.  My copy is well worn.

 

https://www.amazon.c...d/dp/0999470906

I highly recommend that book. Taught me a lot in a weekend of reading- it's a valuable day to day reference guide. That author really knows his stuff and explains most things in a way that can be grasped.



#4 drd715

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Posted 06 December 2019 - 08:25 PM

Some concerns with using a tuned layered filter with such a steep angle light cone. The light passing through the filter sees a longer path through the medium which can shift the pass band frequencies, if you were using a filter such narrow band filter such as duel or triband narrow band type. Also some notch band light pollution filters might get the blocking frequencies shifted off the lp lines.

On a second thought a ir/uv cut filter is useful to remove ir star bloat with these cameras as they are sensitive to out of focus ir above the ha line.

Final answer is contact the filter manufacturer about light cone angle limits and applicable usage of thir filter.

Not applicable to the noted color camera (well maybe if collecting ha only), but a narrow band ha filter from one manufacturer is made in two versions- one for low F numbers and one for longer F numbers (to tune the passband to the cone angle).

Sent from my SM-N950U using Tapatalk

#5 arrowspace90

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Posted 07 December 2019 - 02:16 PM

From my own experience so far, it's obvious that these threads are read/searched long after the comments are made.

 

I called the dude at Starizona and he recommended that I leave the clear, secondary window filter in my RASA 8, and in the filter drawer I purchased, insert the OptiLong light pollution filter.

 

Ok, not cheap, about the same price as the Celestron at a bit over $200.  


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#6 caseyfinn

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Posted 08 December 2019 - 01:45 AM

Depends on what you want to take pictures of. For your color camera you don’t really need anything besides the above mentioned ir/uv cut filter for galaxy’s like M32 or M33. I got the Celestron screw in one and after using it I’d rather have a two inch I could easily change out in the filter slide.  For increased Ha in something like the California nebula my Omega Dmg light pollution filter works well with the Rasa (good price alsoj. For mono the Baader high speed are great paired with a Asi1600mm. Also, a wide band (12nm) ha Filter could be a lot of fun with your camera when the moon is strong.

Must have on that scope are: dew shield to put a light panel on top for flats, 3D printed cable router to remove the funky spikes around bright stars and the Celestron focuser.  

Have fun that’s a great platform and remember to experiment...a lot. F2 is completely different than F5.



#7 arrowspace90

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Posted 08 December 2019 - 08:22 AM

Depends on what you want to take pictures of. For your color camera you don’t really need anything besides the above mentioned ir/uv cut filter for galaxy’s like M32 or M33. I got the Celestron screw in one and after using it I’d rather have a two inch I could easily change out in the filter slide.  For increased Ha in something like the California nebula my Omega Dmg light pollution filter works well with the Rasa (good price alsoj. For mono the Baader high speed are great paired with a Asi1600mm. Also, a wide band (12nm) ha Filter could be a lot of fun with your camera when the moon is strong.

Must have on that scope are: dew shield to put a light panel on top for flats, 3D printed cable router to remove the funky spikes around bright stars and the Celestron focuser.  

Have fun that’s a great platform and remember to experiment...a lot. F2 is completely different than F5.

Ah yes the focusing motor, I have been reading about it.  At least it’s not a thousand bucks like so many things seem to be.




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