22 replies to this topic

[Phil Cowell]

Is there any indication Celestron is going to produce a 14" RASA?

 

[Augustus]

The weight gain compared to an 11" would be enormous, with little light gain.

[Lucullus]

How do you know this?

[Augustus]

How do you know this?

The C14 compared to the C11...

[John Boudreau]

Is there any indication Celestron is going to produce a 14" RASA?

Apparently the possibility of custom producing a limited # of C14 RASAs has been looked into for a satellite tracking program. Don't know if any were ever really built. Such a RASA is mentioned in this PDF presentation:

http://www.amostech....r/Ackermann.pdf

 

One of the authors of this paper is Mark Ackermann, who co-designed the 11" RASA with David Rowe. Also listed below Ackermann is Eric Kopit of Celestron.

 

Whether or not it eventually reaches the point of production by Celestron---- who knows? But it's apparently at least been designed.

[Phil Cowell]

Weight is not an issue, check the mounts in my sig. I already have the 11" RASA and the 14" RASA if it is made would be a worthwhile upgrade in my opinion. I have a C14 and C11 and to me the difference is noticeable. As dedicated imaging platforms with both around F2 even more so. 

Opinions aside has anyone heard if a 14" RASA is on the cards?

 

 

How do you know this?

The C14 compared to the C11...

 

[Phil Cowell]

Thanks for the info. I'll keep my fingers crossed.

 

 

Is there any indication Celestron is going to produce a 14" RASA?

Apparently the possibility of custom producing a limited # of C14 RASAs has been looked into for a satellite tracking program. Don't know if any were ever really built. Such a RASA is mentioned in this PDF presentation:

http://www.amostech....r/Ackermann.pdf

 

One of the authors of this paper is Mark Ackermann, who co-designed the 11" RASA with David Rowe. Also listed below Ackermann is Eric Kopit of Celestron.

 

Whether or not it eventually reaches the point of production by Celestron---- who knows? But it's apparently at least been designed.

 

Edited by Phil Cowell, 02 October 2016 - 08:16 PM.

[GJJim]

If the focal ratios are the same, then the only benefit of a 14" RASA is a bit more image scale. I doubt the extra weight and expense are worth it. 

[kbastro]

only benefit to a 14" RASA if you are shooting with a 70mm chip,,, other wise a standard 14" edge would be a better choice,,,

as your can use the Edge in triple config. .. f/10, 6.3 & 1.9. with rasa you only have the one choice. and almost half the cost,,,,,

 

kb

[jhayes_tucson]

Since Celestron accidentally announced it at the last AIC meeting in a brochure that they distributed, I'm pretty sure that they've been thinking about it for some time.  In fact, I heard that they showed it off at the Astronomy conference in Hawaii last week.  I don't know if they've delivered any or what their plans are for announcing it to the general market but if you want one, my guess is that it will show up one of these days, but it's hard to say exactly when.  My feeling is that there might be a few improvements over the R11 but we'll have to see what it looks like when it hits the market.

 

I personally agree with kb that a C14 Edge offers much greater versatility but for those who only want to shoot wide field, the RASA is specifically designed for that capability.

 

John

[Phil Cowell]

I have a 14" Edge. My 11" RASA is very convenient. No swapping things around and the dedicated use is nice.

If they bring it to market I'll probably grab one and upgrade my camera.

 

Since Celestron accidentally announced it at the last AIC meeting in a brochure that they distributed, I'm pretty sure that they've been thinking about it for some time.  In fact, I heard that they showed it off at the Astronomy conference in Hawaii last week.  I don't know if they've delivered any or what their plans are for announcing it to the general market but if you want one, my guess is that it will show up one of these days, but it's hard to say exactly when.  My feeling is that there might be a few improvements over the R11 but we'll have to see what it looks like when it hits the market.

 

I personally agree with kb that a C14 Edge offers much greater versatility but for those who only want to shoot wide field, the RASA is specifically designed for that capability.

 

John

[rmollise]

They might... but...why?

The advantage would be more image scale...which is not what most people buying one of these scopes are after.

[jhayes_tucson]

Sure the image scale increases with a larger scope but the FOV of a 14" RASA with a large chip is still huge.  Here are some other possible reasons for a bigger version:

1)  Bigger telescopes always gather more light and go deeper.  A 14" gathers about 62% more light than an 11".

2)  Bigger telescopes have better optical resolution that scales with the inverse of the aperture.

3)  There is probably a market for a large, wide field scope.  The fact that Celestron showed it at a professional astronomy meeting indicates that they have some interest from the sky survey folks.  Not all programs can jump into the realm of the LSST.  It is certainly true that market size diminishes with size and price but a 14" RASA leverages the capability that Celestron already has for manufacturing a scope of this side.

 

In my mind, the real limitation of the RASA lies in the sensor.  If the RASA systems are designed to be diffraction limited, it's hard to find any large CCD sensor with sufficiently small pixels to optimize sampling.  That limits the system to the large, small pixel chips found in DSLRs.  That's not a huge limitation but it makes narrowband imaging more difficult.

 

John

[rmollise]

Sure the image scale increases with a larger scope but the FOV of a 14" RASA with a large chip is still huge.  Here are some other possible reasons for a bigger version:

1)  Bigger telescopes always gather more light and go deeper.  A 14" gathers about 62% more light than an 11".

2)  Bigger telescopes have better optical resolution that scales with the inverse of the aperture.

3)  There is probably a market for a large, wide field scope.  The fact that Celestron showed it at a professional astronomy meeting indicates that they have some interest from the sky survey folks.  Not all programs can jump into the realm of the LSST.  It is certainly true that market size diminishes with size and price but a 14" RASA leverages the capability that Celestron already has for manufacturing a scope of this side.

 

In my mind, the real limitation of the RASA lies in the sensor.  If the RASA systems are designed to be diffraction limited, it's hard to find any large CCD sensor with sufficiently small pixels to optimize sampling.  That limits the system to the large, small pixel chips found in DSLRs.  That's not a huge limitation but it makes narrowband imaging more difficult.

 

John

 

Sure, but in the case of extended objects, bigger (aperture) won't go deeper at the same focal ratio, it will only go bigger when imaging, and these scopes are not intended to be used visually. It will deliver more stars and better resolution.

Edited by rmollise, 03 October 2016 - 12:05 PM.

[jhayes_tucson]

... It will deliver more stars and better resolution.

 

 

Thanks for the clarification...that's what I meant.   In the case of an extended object, you are totally correct that it won't go deeper but it's the extra aperture that delivers a bigger (and somewhat sharper) image at the same irradiance as a smaller scope with the same F/#.

John

Edited by jhayes_tucson, 03 October 2016 - 12:49 PM.

[DuncanM]

Hopefully Celestron will improve the mirror support system in the 14in RASA. 

[GJJim]

Hopefully Celestron will improve the mirror support system in the 14in RASA. 

Are you suggesting that collimation at f/2.2 might be critical?   I've not seen how Celestron supports and guides the primary in these OTAs, are they using anything similar to the internal Crayford focuser in the new Meade ACFs?

[DuncanM]

 

Hopefully Celestron will improve the mirror support system in the 14in RASA. 

Are you suggesting that collimation at f/2.2 might be critical?   I've not seen how Celestron supports and guides the primary in these OTAs, are they using anything similar to the internal Crayford focuser in the new Meade ACFs?

 

Celestron appears to be using their usual SCT moving mirror focusing system. The Meade internal crayford would be a step up.

[kbastro]

11" rasa has lateral mirror movement side to side,,, mirror shift up and down has been controlled fairly well,,, the extra weight of a 14" mirror

would need a superior mirror supports/control, a fixed primary would be the best choice for the 14"

 

kb

[akulapanam]

The slightly longer focal length would give more camera options for 1" sec resolution imaging. I'll take one if Celestron wants to sell me one

Edited by akulapanam, 05 October 2016 - 02:22 PM.

[celestroneric]

Hi everyone, it's me again!

 

Yes the RASA 36cm does exist. You can see it here:

https://twitter.com/Celestroneric

 

Yes, we have built and shipped units.

 

Now, this telescope was specifically designed for Space Surveillance applications, and is not currently available to the general public.The interest and demand has been very strong from that industry, so I currently don't envision this being available to the public for at least a couple of years from now. Certainly not before 2018.

 

Space surveillance (SSA) is much different than capturing "pretty pictures". Yes, RASA 36cm is designed for a large sensor, take a look at the FLI 50100, this provides the greatest etendue. For SSA work, it is very common for the cost of the camera to exceed the cost of the optical tube. RASA 36cm also has extended spectral range (400-900nm), and does have a different focuser than our other catadioptric telescopes (thanks John Hayes!). Has other features similar to the 11" version, like cooling fan, removable "clear filter", dovetail bars, etc.

 

The smaller RASA 11" is also becoming widely adopted for Space Surveillance work. My Twitter page has some info about Embry-Riddle Aeronautics University (ERAU) using our RASA 11" to detect and track Cubesats. 

 

I do think the RASA 11" is probably better for most amateur astronomy applications, as the RASA 36cm is really only suited for observatory use, it's just too big and heavy for most, and most are not using a large enough sensor to take full advantage of the RASA 36cm capability. It also costs almost three times more than the RASA 11"!

 

I do think the extended spectral range is very cool. This scope is capable of infra-red imaging! Granted, the transmission (and camera sensitivity) typically falls off after 700-750nm, but there is still good data out there to be captured. I do think that amateur astronomy will get more into IR imaging in the future, it's like a whole new world out there!

 

If this all get your juices flowing, as it does mine, then read the RASA Whitepaper, written by Richard Berry along with myself, Dave Rowe, Mark Ackermann, and Corey Lee. Here it is:

 

http://www.celestron...per_low_res.pdf

 

Enjoy!

 

-E
 

[akulapanam]

Hi everyone, it's me again!

 

Yes the RASA 36cm does exist. You can see it here:

https://twitter.com/Celestroneric

 

Yes, we have built and shipped units.

 

Now, this telescope was specifically designed for Space Surveillance applications, and is not currently available to the general public.The interest and demand has been very strong from that industry, so I currently don't envision this being available to the public for at least a couple of years from now. Certainly not before 2018.

 

Space surveillance (SSA) is much different than capturing "pretty pictures". Yes, RASA 36cm is designed for a large sensor, take a look at the FLI 50100, this provides the greatest etendue. For SSA work, it is very common for the cost of the camera to exceed the cost of the optical tube. RASA 36cm also has extended spectral range (400-900nm), and does have a different focuser than our other catadioptric telescopes (thanks John Hayes!). Has other features similar to the 11" version, like cooling fan, removable "clear filter", dovetail bars, etc.

 

The smaller RASA 11" is also becoming widely adopted for Space Surveillance work. My Twitter page has some info about Embry-Riddle Aeronautics University (ERAU) using our RASA 11" to detect and track Cubesats. 

 

I do think the RASA 11" is probably better for most amateur astronomy applications, as the RASA 36cm is really only suited for observatory use, it's just too big and heavy for most, and most are not using a large enough sensor to take full advantage of the RASA 36cm capability. It also costs almost three times more than the RASA 11"!

 

I do think the extended spectral range is very cool. This scope is capable of infra-red imaging! Granted, the transmission (and camera sensitivity) typically falls off after 700-750nm, but there is still good data out there to be captured. I do think that amateur astronomy will get more into IR imaging in the future, it's like a whole new world out there!

 

If this all get your juices flowing, as it does mine, then read the RASA Whitepaper, written by Richard Berry along with myself, Dave Rowe, Mark Ackermann, and Corey Lee. Here it is:

 

http://www.celestron...per_low_res.pdf

 

Enjoy!

 

-E
 

 

I hope you will consider making the scope available to the public sooner rather than later.  The extended spectral range (see Rolf Olsen's work), the ability to put a QSI camera in front with less obstruction, and a better focuser are also great adds.  Personally I like the slightly longer focal length because it gives you the ability to do high resolution (1" or below) with a greater range of cameras with a very generous field and high etendue.

[Phil Cowell]

I look forward to the 14" becoming available. It would live in an observatory, the 11" will keep me busy until then.

 

Hi everyone, it's me again!

 

Yes the RASA 36cm does exist. You can see it here:

https://twitter.com/Celestroneric

 

Yes, we have built and shipped units.

 

Now, this telescope was specifically designed for Space Surveillance applications, and is not currently available to the general public.The interest and demand has been very strong from that industry, so I currently don't envision this being available to the public for at least a couple of years from now. Certainly not before 2018.

 

Space surveillance (SSA) is much different than capturing "pretty pictures". Yes, RASA 36cm is designed for a large sensor, take a look at the FLI 50100, this provides the greatest etendue. For SSA work, it is very common for the cost of the camera to exceed the cost of the optical tube. RASA 36cm also has extended spectral range (400-900nm), and does have a different focuser than our other catadioptric telescopes (thanks John Hayes!). Has other features similar to the 11" version, like cooling fan, removable "clear filter", dovetail bars, etc.

 

The smaller RASA 11" is also becoming widely adopted for Space Surveillance work. My Twitter page has some info about Embry-Riddle Aeronautics University (ERAU) using our RASA 11" to detect and track Cubesats. 

 

I do think the RASA 11" is probably better for most amateur astronomy applications, as the RASA 36cm is really only suited for observatory use, it's just too big and heavy for most, and most are not using a large enough sensor to take full advantage of the RASA 36cm capability. It also costs almost three times more than the RASA 11"!

 

I do think the extended spectral range is very cool. This scope is capable of infra-red imaging! Granted, the transmission (and camera sensitivity) typically falls off after 700-750nm, but there is still good data out there to be captured. I do think that amateur astronomy will get more into IR imaging in the future, it's like a whole new world out there!

 

If this all get your juices flowing, as it does mine, then read the RASA Whitepaper, written by Richard Berry along with myself, Dave Rowe, Mark Ackermann, and Corey Lee. Here it is:

 

http://www.celestron...per_low_res.pdf

 

Enjoy!

 

-E