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Looking to upgrade from the 16803 FLI.

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#1 aitke12

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Posted 17 September 2019 - 12:34 PM

Current set up is a 24" Planewave and running a FLI 16803. and want to upgrade to a bigger more modern chip with high Megapixel count. budget is around 15 to 20K. I have looked at the FLI ML50100. any suggestions. Not looking to take a pretty photo, but more along the lines of scientific research.  Thanks for the help. 



#2 jhayes_tucson

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Posted 17 September 2019 - 01:56 PM

I can understand the desire for a bigger chip but you should be careful about optimizing the pixel size.  How good is the seeing in your location and how close to being sampling limited are you by the 9 micron pixels in the 16803 chip?

 

John



#3 fetoma

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Posted 17 September 2019 - 01:59 PM

Gsense6060 maybe. 1 micron bigger pixel though.



#4 Coconuts

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Posted 17 September 2019 - 02:10 PM

The Gsense 6060 is an upgrade, all right, but any camera based on it sure won't fit within his $15-$20K budget.  The FLI camera based on this sensor starts at $37,850, and depending on what grade sensor you want, can go as high as $368K!

 

https://www.tolgaast...epler-6060.html

 

All the best,

 

Kevin



#5 555aaa

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Posted 17 September 2019 - 02:26 PM

Do you have any more specifics on the science projects since that defines what performance is desired from the camera - spectral response, linearity, uniformity, etc. Is it fast survey work or slow but precise "point and stare" work?

 

On a different topic, have you considered doing spectroscopy using the Aply (Shelyak) fiber fed echelle spectrograph? That should give you some really outstanding results on that telescope. You could buy that for less than the cost of a new camera.


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#6 aitke12

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Posted 18 September 2019 - 10:08 AM

way out of the Budget. Yikes!

The Gsense 6060 is an upgrade, all right, but any camera based on it sure won't fit within his $15-$20K budget.  The FLI camera based on this sensor starts at $37,850, and depending on what grade sensor you want, can go as high as $368K!

 

https://www.tolgaast...epler-6060.html

 

All the best,

 

Kevin



#7 aitke12

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Posted 18 September 2019 - 10:09 AM

AAVSO Observations and Asteroid hunting. 

Do you have any more specifics on the science projects since that defines what performance is desired from the camera - spectral response, linearity, uniformity, etc. Is it fast survey work or slow but precise "point and stare" work?

 

On a different topic, have you considered doing spectroscopy using the Aply (Shelyak) fiber fed echelle spectrograph? That should give you some really outstanding results on that telescope. You could buy that for less than the cost of a new camera.



#8 freestar8n

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Posted 18 September 2019 - 05:12 PM

AAVSO Observations and Asteroid hunting. 

If you plan to search for new asteroids in survey mode then I would get the reducer for the 24" if you don't already have it - and get the biggest detector you can regardless of pixel size or sensor noise - as long as the noise isn't too bad.  The ML50100 would unfortunately be smaller pixels with higher read noise - as opposed to a typical cmos option of smaller pixels but much lower read noise.  If you aren't doing narrowband work then the increased read noise may not matter much.  And since it is interline you would be able to work in video mode - which may be useful.

 

But if you want to move to a larger and 'more modern chip' - it's unfortunate if you can't fit a big cmos in the budget.

 

On the other hand, if you aren't in survey mode or you don't have the reducer - just combining a reducer with the GSense 4040 would be the same size sensor but lower read noise and video mode - and 'more modern' - and more versatile for a number of scientific applications.

 

Frank



#9 555aaa

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Posted 19 September 2019 - 02:36 AM

AAVSO Observations and Asteroid hunting. 

The graph below might be helpful in predicting the system performance for asteroid observations, especially for NEO confirmation, which would be a good use for this telescope. The blue diamonds are a plot of tonight's near earth orbit confirmation asteroid list, showing the asteroid magnitude on the horizontal axis and the speed of the asteroid on the vertical axis. The easiest one to observe is the slowest moving and brightest, and in this case there is one at about 19th mag and moving about 0.4 arc seconds per minute. That one is easily measured with small amateur telescopes. The red squares are the predicted performance for a 0.5m telescope, with a camera binned to 1.2 arc second pixels under 2.5 arc second seeing (which will produce a meaningful astrometric residual), 20.5 mag per arc second sky background, and about 0.5 quantum efficiency on the camera, and assuming no filter and a typical CCD response spectrum. The exposure limiting time in this plot is the time for the asteroid to move 3.5 arc seconds with is an "ovalization" of the image of 3.5/2.5 which is reasonable, and the exposure time is for a SNR of 8 which is low but detectable. My little calculator says that for say 19th magnitude you can get to SNR of 8 in a 12 second exposure, but for 22nd magnitude you need 1700 seconds. So the 12 second exposure gives you a 3.5 arc second 'trail' on your image if the asteroid is moving at 17.5 arc seconds per minute.

 

In this plot, it says that tonight you could perform useful confirmation observations of seven asteroids on the list (well probably not since I included the ones in the southern hemisphere) but it is enough targets that it would occupy one telescope all night, since for each asteroid you need about an hour's worth of data.

 

Now, for fast moving asteroids, most people use a 'track and stack' method and that can greatly extend the useful exposure time, but the key for that to work well is that you really need fast download out of the camera. The people who are doing that well (e.g. Northolt Branch observatory) all use fast CMOS cameras. I do this type of work using an old interline CCD and the problem I have with the track and stack method is the download time consumes far too much of the imaging time. A big drawback of the track and stack method is that you have to have prior knowledge of the asteroid position angle and also in a dense star field, the stacked image is so contaminated with the arcs of field stars that it is pretty difficult to find and measure the target.

 

For fast cadence variable stars you also want the fast download, but the camera you have now probably is plenty adequate as long as it can be cooled sufficiently for most variables or expoplanet work if your cadence is around a minute or so. You can do the same type of calculation for variable stars (what is the fastest observational cadence versus magnitude) except bump up the SNR to your target SNR for the science and then cut the flux based on the spectral width of the filter. For precision photometry I think I would stick with the traditional CCD design.

 

neocp_half_meter.png

 

 

-Bruce V

Burnt Tree Hill Observatory U63


Edited by 555aaa, 19 September 2019 - 02:43 AM.


#10 Dan Crowson

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Posted 19 September 2019 - 01:20 PM

Bruce,

 

can you point out where you can pull the confirmation list in the post above?

 

Dan



#11 555aaa

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Posted 19 September 2019 - 02:35 PM

Bruce,

 

can you point out where you can pull the confirmation list in the post above?

 

Dan

https://minorplanetc...rm_tabular.html




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