lenses / objectives / mirrors for below 405nm

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
Post Reply
TheSkyBurner
Im an EXPERT!
Im an EXPERT!
Posts: 321
Joined: Sat May 05, 2018 7:55 pm

lenses / objectives / mirrors for below 405nm

Post by TheSkyBurner » Sun May 06, 2018 12:01 am

I would like to dedicate this thread to optics which are known to be only useful for wavelegnths below 405nm.

Telescope objectives that are known to be >.85 strehl performers below 405nm are welcome to be posted but please keep the topic appropriate.

Please, Nothing about G-band. Nothing about h-alpha, nothing about IR or near IR.

Please do not change the topic to area's not supportive of near UV light.


https://www.edmundoptics.com/optics/opt ... -pcx-lens/

Thank you!

(if you know what the ratings on a televue powermate below 405nm are, please post that information!)


TheSkyBurner
Im an EXPERT!
Im an EXPERT!
Posts: 321
Joined: Sat May 05, 2018 7:55 pm

Re: lenses / objectives / mirrors for below 405nm

Post by TheSkyBurner » Sun May 06, 2018 4:13 am


User avatar
Merlin66
Librarian
Librarian
Posts: 3122
Joined: Tue Dec 13, 2011 1:23 pm
Location: St Leonards, Australia
Contact:

Re: lenses / objectives / mirrors for below 405nm

Post by Merlin66 » Sun May 06, 2018 6:43 am

How far into the UV do you want to consider?
I have successfully imaged stellar spectra with a Genesis and ATiK 314 down to 375nm.
You also have to consider the CCD response in the UV......
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

TheSkyBurner
Im an EXPERT!
Im an EXPERT!
Posts: 321
Joined: Sat May 05, 2018 7:55 pm

Re: lenses / objectives / mirrors for below 405nm

Post by TheSkyBurner » Sun May 06, 2018 8:41 am

Merlin66: Spectral curve regarding CCD and CMOS performance below 405nm should definitely be posted here!

Anything down to 325nm will be useful and likely the amateur limit. Anything lower is getting close to the danger zone for most people to comfortably admire.

Spectral response is of course the key to performance with things the human eye cannot see..

Although this is a solar forum, the information will be useful all around and stellar phenomena is a good area. Most amateurs just use the lower wavelengths for nature photography.

The mercury I-line is at 365nm and I do not believe anybody has focused on that with solar imaging yet due to the knowledge of equipment being scare.

christian viladrich
Im an EXPERT!
Im an EXPERT!
Posts: 357
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Contact:

Re: lenses / objectives / mirrors for below 405nm

Post by christian viladrich » Sun May 06, 2018 9:19 am

I would include the Takahashi TOA 150 (down to 350 nm).
If Balow lens are to be included, I would add Baader FFC. (down to 350 nm).

I don't know whether this is relevant to the post, but I have OSLO simulations of a variety of Barlow lenses down to 350 nm:
http://astrosurf.com/viladrich/astro/in ... Barlow.htm
Christian Viladrich
Co-author of "Astronomie Planétaire"
http://www.astroplanetes.com/

christian viladrich
Im an EXPERT!
Im an EXPERT!
Posts: 357
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Contact:

Re: lenses / objectives / mirrors for below 405nm

Post by christian viladrich » Sun May 06, 2018 9:26 am

Measurements of quantum efficiency of various sensors (source : Christian Buil)
Image
Image
Christian Viladrich
Co-author of "Astronomie Planétaire"
http://www.astroplanetes.com/

TheSkyBurner
Im an EXPERT!
Im an EXPERT!
Posts: 321
Joined: Sat May 05, 2018 7:55 pm

Re: lenses / objectives / mirrors for below 405nm

Post by TheSkyBurner » Sun May 06, 2018 11:46 am

Lol at toa150. A $10,000 telescope better perform at .99 strehl from 350 to 900 nm. ;). Lol...

TheSkyBurner
Im an EXPERT!
Im an EXPERT!
Posts: 321
Joined: Sat May 05, 2018 7:55 pm

Re: lenses / objectives / mirrors for below 405nm

Post by TheSkyBurner » Thu May 10, 2018 2:43 pm


Post Reply

Who is online

Users browsing this forum: Bing [Bot] and 2 guests