Ca K telescope

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
User avatar
grimble_cornet
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 3537
Joined: Tue Jul 10, 2012 5:10 pm
Location: UK West Midlands
Been thanked: 47 times

Re: Ca K telescope

Post by grimble_cornet »

image.jpg
image.jpg
After drooling over images posted by Mark, Alexandra and others, I decided to buy a Lunt CaK 60 telescope.
I quite like the idea of a dedicated scope which I can use mounted side by side with an Ha or white light scope and I'm pretty happy with my first images.

However, I also want to use the CaK 1200 module with my Equinox 80 and even my Equinox 120 for greater resolution.
This is where the problem starts!
The two Equinox scopes have identical draw tubes and focusers - both have a very small step about 2 inches in. It is very small but just enough to stop the CaK module going past it which leaves about half of the black tube sticking out! Not surprisingly this makes it impossible to reach focus either visually or with a camera. Don't really fancy reaming out the Equinox tube so what else can I try?
My ASI 120 camera has a T-thread and I can screw this directly to the CaK prism if I unscrew the eyepiece holder. This allows me to reach focus and the Equinox 80 does seem to give slightly better images than the Lunt 60 unit. However, I can see no obvious way to use a Barlow or Powermate in this optical train so the resolution I can record is limited.
I assume that the black tube with its silver filters at each end is acting as an energy rejection filter? I wonder if I could remove this and use the remainder of the CaK unit with a Baader Ceramic Wedge or even a Solarfilm filter? Not sure if I can find an adaptor to replace the black filter tube with a plain 2" tube?
Any advice from those members who have travelled this road before would be most welcome.

Mike


.

.



.


Mike Garbett

Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
User avatar
swisswalter
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 17948
Joined: Thu Feb 06, 2014 4:28 am
Location: Switzerland
Been thanked: 1 time
Contact:

Re: Ca K telescope

Post by swisswalter »

Hi Mike

using a herschel wedge, followed by a K-line filter, followed by the LUNT CaK filter, followed by an UV/IR cut from beloptik works perfect if you have enough inward travel of the focuser


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)
User avatar
grimble_cornet
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 3537
Joined: Tue Jul 10, 2012 5:10 pm
Location: UK West Midlands
Been thanked: 47 times

Re: Ca K telescope

Post by grimble_cornet »

Thanks Walter but I'm now confused!
I had assumed that the black tube was just reducing the sunlight intensity and that all of the CaK components were in the prism?
Your answer suggests that some of them (K line filter ?) are in the tube and I would have to provide alternative ones if I removed the tube and replaced it with a Herschel wedge?


.

.



.


Mike Garbett

Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: Ca K telescope

Post by marktownley »

Hi Mike.

I can't offer anything much here i'm afraid; some focusers do have these steps, and they aren't any good with the Lunt CaK. Short of reducing the tube length of your OTAs, getting different focusers for them or cutting off the end section of the focuser tube with the notch that's about it. Great opening images btw!

Mark


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
User avatar
grimble_cornet
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 3537
Joined: Tue Jul 10, 2012 5:10 pm
Location: UK West Midlands
Been thanked: 47 times

Re: Ca K telescope

Post by grimble_cornet »

Thanks Mark - I was afraid that might be the case :evil:
I may try to take the Equinox tube apart and see how easy it would be to remove the step or...... following the discussions here, consider a long focal length achromat.


.

.



.


Mike Garbett

Selection of Solar and Deep Sky images on Flickr: https://www.flickr.com/photos/mikegarbett/
User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: Ca K telescope

Post by marktownley »

see if you can pick up a tal100R ;)


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
User avatar
sullij1
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2249
Joined: Wed Mar 28, 2012 4:29 am
Been thanked: 1 time

Re: Ca K telescope

Post by sullij1 »

Sorry, Just saw this. Yep you need the 2 filters contained in the black tube. The module will not function without them.

As for the baffle in the focuser, See if you can find a piece of plumbing pipe slightly smaller than the focuser diameter but larger than the baffle with enough length to leave you with 6 inch sticking out of the focuser end. Remove the focuser tube from the focuser. With the pipe inserted in the focuser and against the baffel, strike the pipe with a hammer until you have knocked the baffel out of the focuser tube. The baffle is glued or spot welded to the inside of the focuser and it will not take too much of a blow to knock it free.

I have done this in the past.


Look Up!
User avatar
swisswalter
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 17948
Joined: Thu Feb 06, 2014 4:28 am
Location: Switzerland
Been thanked: 1 time
Contact:

Re: Ca K telescope

Post by swisswalter »

Hi Joe

the golden tube from a PST has just about the right diameter ;-)


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)
Post Reply