Rassa 8" & Rassa 11"

[Constant (David)]

After traversing the forums, a few reviews of the extraordinary Rassa series can be found. A number of these reviews/discussions are getting a Little long in the tooth. What's the current consensus on the Rassa series? At close to $6k the 11" has many exciting rivals, they're many possibilities at this price point
Are the Rassa's difficult to use?
At the crazy low f numbers is finding/maintaining focus difficult? What cameras have proven themselves on the Rassa's (spacing issues discussed)
Id love to hear from owners of Rassa's..... Would they purchase another Rassa or are the fininiky machinations of such low f numbers too difficult for mere mortals (yours truly)?
Currently I'm using a 130mm f7 APO triplet, no fuss, simple point and shoot, hence my concerns with the Rassa's .....
Your thoughts please.

[gregbradley]

Another way of finding out is doing a search on Astrobin for RASA 11 and see what comes up and what gear they were using.

The ASI6200/QHY600 full frame camera is very fussy with regards to tilt. Tilt is also usually more pronounced with faster scopes.

So given that I imagine it would be tricky to get it set but obviously some have mastered it.

The smaller APS sized ASI2600M or MC or QHY equivalent may be a lot less demanding.

For example with my AP RHA 305 F3.8, my QHY294M needs no adjustment for tilt. The QHY600M does and is a bit fussy about it. Not impossible (tilt never seems to be dead easy) but it will take a little while.

Greg.

Originally Posted by Constant

After traversing the forums, a few reviews of the extraordinary Rassa series can be found. A number of these reviews/discussions are getting a Little long in the tooth. What's the current consensus on the Rassa series? At close to $6k the 11" has many exciting rivals, they're many possibilities at this price point
Are the Rassa's difficult to use?
At the crazy low f numbers is finding/maintaining focus difficult? What cameras have proven themselves on the Rassa's (spacing issues discussed)
Id love to hear from owners of Rassa's..... Would they purchase another Rassa or are the fininiky machinations of such low f numbers too difficult for mere mortals (yours truly)?
Currently I'm using a 130mm f7 APO triplet, no fuss, simple point and shoot, hence my concerns with the Rassa's .....
Your thoughts please.

[JA]

Originally Posted by gregbradley

Another way of finding out is doing a search on Astrobin for RASA 11 and see what comes up and what gear they were using.

The ASI6200/QHY600 full frame camera is very fussy with regards to tilt. Tilt is also usually more pronounced with faster scopes.

So given that I imagine it would be tricky to get it set but obviously some have mastered it.

The smaller APS sized ASI2600M or MC or QHY equivalent may be a lot less demanding.

For example with my AP RHA 305 F3.8, my QHY294M needs no adjustment for tilt. The QHY600M does and is a bit fussy about it. Not impossible (tilt never seems to be dead easy) but it will take a little while.

Greg.

Of course you're absolutely right Greg: APS-c sized and smaller sensors will be much kinder to tilt as well as any other potential aberrations towards the edges of the image circle. The only downside is that you'd be leaving a lot of light on the table (~60% unused) compared with using all of the RASA 11's full frame image circle.

Best
JA

[gregbradley]

Yes but judging from the wonderful full frame CMOS images on that setup on Astrobin it would be worth the effort.

I must admit I never thought a Celestron product would produce such high end images.

Focuser shift may be another issue.

Greg.

Originally Posted by Constant

After traversing the forums, a few reviews of the extraordinary Rassa series can be found. A number of these reviews/discussions are getting a Little long in the tooth. What's the current consensus on the Rassa series? At close to $6k the 11" has many exciting rivals, they're many possibilities at this price point
Are the Rassa's difficult to use?
At the crazy low f numbers is finding/maintaining focus difficult? What cameras have proven themselves on the Rassa's (spacing issues discussed)
Id love to hear from owners of Rassa's..... Would they purchase another Rassa or are the fininiky machinations of such low f numbers too difficult for mere mortals (yours truly)?
Currently I'm using a 130mm f7 APO triplet, no fuss, simple point and shoot, hence my concerns with the Rassa's .....
Your thoughts please.

Originally Posted by JA

Of course you're absolutely right Greg: APS-c sized and smaller sensors will be much kinder to tilt as well as any other potential aberrations towards the edges of the image circle. The only downside is that you'd be leaving a lot of light on the table (~60% unused) compared with using all of the RASA 11's full frame image circle.

Best
JA

[Constant (David)]

Originally Posted by gregbradley

Yes but judging from the wonderful full frame CMOS images on that setup on Astrobin it would be worth the effort.

I must admit I never thought a Celestron product would produce such high end images.

Focuser shift may be another issue.

Greg.

Gentlemen,

Many thanks, your reinforcing my preconceived ideas of high precision. Frankly my hands shake too much, even the thought of adjusting tilt angles adjacent to a very expensive corrector plates make my hands shake.
Maybe this is best left to those with good eyes and steady hands

David