#1  
Old 01-11-2017, 07:37 AM
garymck (Gary)
Registered User

garymck is offline
 
Join Date: Aug 2005
Location: Geelong
Posts: 788
What focal length?

Hi,
want to buy a new scope for imaging wide field narrow band from my orange zone home in Geelong.

Looking to find the optimal size/focal length to frame a good number of narrow band objects. Hopefully want to find a scope that has a focuser adaptable to mechanising rotation to make mosaics easier.

Budget is up to 4K. Hope to find a scope no slower than F5.5

Will be used with a KAF8300 chip.

Esprit's look OK, but hate the focus rotation method, cludgy and rough on the one example I've seen in the flesh, and not automatable.

Suggestions?

TIA
cheers
Gary
Reply With Quote
  #2  
Old 01-11-2017, 04:55 PM
Alexborek (Alexandre)
Registered User

Alexborek is offline
 
Join Date: Sep 2017
Location: Sydney
Posts: 5
To be honest with you Gary, get a RASA. Amazingly fast and widefield. I'm not sure you can grab one of these for 4k... But you should give it a try. The Bintel's one is 11" aperture and 680mm FL, yet i'm pretty sure you can find some closer to RCs specs.
Reply With Quote
  #3  
Old 01-11-2017, 05:25 PM
Andy01's Avatar
Andy01 (Andy)
My God it's full of stars

Andy01 is offline
 
Join Date: Mar 2012
Location: Melbourne
Posts: 3,253
I’m pretty happy with my Stellarvue SV70T & QSI 8300 combo.
Great bang for the buck.
I shoot widefield NB from the ‘burbs in Melbourne
Reply With Quote
  #4  
Old 01-11-2017, 06:04 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
Another option would be to get a Borg. They’re reasonably expensive but very good quality and umpteen combinations that can be achieved.
Reply With Quote
  #5  
Old 01-11-2017, 06:05 PM
garymck (Gary)
Registered User

garymck is offline
 
Join Date: Aug 2005
Location: Geelong
Posts: 788
Quote:
Originally Posted by Alexborek View Post
To be honest with you Gary, get a RASA. Amazingly fast and widefield. I'm not sure you can grab one of these for 4k... But you should give it a try. The Bintel's one is 11" aperture and 680mm FL, yet i'm pretty sure you can find some closer to RCs specs.
Unfortunately there is only 1 RASA and it's just shy of $10K !! Slightly out of budget I'm afraid...
cheers
Gary
Reply With Quote
  #6  
Old 01-11-2017, 07:17 PM
Slawomir's Avatar
Slawomir (Suavi)
Registered User

Slawomir is offline
 
Join Date: Sep 2014
Location: North Queensland
Posts: 3,240
Perhaps a telescope from TS would fit your criteria?

For example their Imaging Star 130 mm f/5 triplet should fit within your budget landed +taxes. I don't have any experience with this particular model, but I really liked their 102mm ED doublet that I used for a couple of years.
Reply With Quote
  #7  
Old 01-11-2017, 08:12 PM
traveller's Avatar
traveller (Bo)
Not enough time and money

traveller is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 2,133
Can you stretch your budget and aim for a second hand FSQ106?
Reply With Quote
  #8  
Old 01-11-2017, 10:24 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
Quote:
Originally Posted by Slawomir View Post
Perhaps a telescope from TS would fit your criteria?

For example their Imaging Star 130 mm f/5 triplet should fit within your budget landed +taxes. I don't have any experience with this particular model, but I really liked their 102mm ED doublet that I used for a couple of years.
This is virtually identical to the Sky Rover 130mm Sextuplet I’ve got, different focuser but that’s about it.
Reply With Quote
  #9  
Old 02-11-2017, 05:16 AM
Slawomir's Avatar
Slawomir (Suavi)
Registered User

Slawomir is offline
 
Join Date: Sep 2014
Location: North Queensland
Posts: 3,240
Quote:
Originally Posted by Atmos View Post
This is virtually identical to the Sky Rover 130mm Sextuplet I’ve got, different focuser but that’s about it.
Would you recommend your Sky Rover Colin? From your images and feedback I gather it is a nice telescope and a good performer
Reply With Quote
  #10  
Old 02-11-2017, 05:39 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
The Teleskop-Express Photoline series has several scopes that would suit within your budget, running at f5.5, and using FPL-53 objectives. While native f7 they reduce using the 3" screw on Photoline Reducer Corrector to f5.5. A triplet, running the four-element reducer is a great combination. The Image Star range with in built correctors are more costly and you lose the option of using them visually should you wish to do so.
I have the 115mm Photoline Triplet APO running at f5.5 and it is used for shooting narrowband. If you want even wider field options, the TS80 Triplet APO is a bargain, it reduces (using the same 3" Photoline reducer corrector, down to f5.5 (440mm fl).
You could look at Hyperstar options, say with a Celestron 8" SCT, or Edge HD, running the front mount camera but you need to use a camera like the ASI1600 to avoid increases on obstruction. This config wpuld be more expensive than the TS Photolime APOs but it is much faster at f2, however you may need to buy high speed narrowband filters.
Reply With Quote
  #11  
Old 02-11-2017, 06:06 AM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
Quote:
Originally Posted by Slawomir View Post
Would you recommend your Sky Rover Colin? From your images and feedback I gather it is a nice telescope and a good performer
Let’s just say that it’ll take the Nikon D810s quite small pixels at the edge of field with very little distortion

On the website it says it has a 55mm imaging circle of which is believe if you were to use something like the 16803 sensor with its 9 micron pixels.

I’ve just decided to go bigger and faster so mine will probably be up for sale soon enough
Reply With Quote
  #12  
Old 02-11-2017, 07:03 AM
garymck (Gary)
Registered User

garymck is offline
 
Join Date: Aug 2005
Location: Geelong
Posts: 788
Hi all,
thank you all for your suggestions:

Andy01: Stellavue look OK but perhaps a bit expensive for a "rebranded" scope, think there might be better value options.

Atmos: Had a look at Borg whilst on a recent trip to Japan, looked OK but very expensive for doublets that by some reports show a bit of color (short FL?) decided that for that money a Tak might be better :-)

Slawomir and Glend: I think the ultimate choice will come from TS, they seem to have a good rep, though I have seen the odd report of a dud scope. They have a nice looking 130mm FPL53 at around 1600 Euro - :-)

Traveller: and FSQ would be nice, but don't come up very often :-(

Decisions! Decisions!

cheers
Gary
Reply With Quote
  #13  
Old 02-11-2017, 08:06 AM
Andy01's Avatar
Andy01 (Andy)
My God it's full of stars

Andy01 is offline
 
Join Date: Mar 2012
Location: Melbourne
Posts: 3,253
Quote:
Originally Posted by garymck View Post
Andy01: Stellavue look OK but perhaps a bit expensive for a "rebranded" scope, think there might be better value options.
Maybe so, but the two APOD’s I received for images taken with mine suggest it’s good value for money...
Reply With Quote
  #14  
Old 02-11-2017, 08:38 AM
garymck (Gary)
Registered User

garymck is offline
 
Join Date: Aug 2005
Location: Geelong
Posts: 788
Quote:
Originally Posted by Andy01 View Post
Maybe so, but the two APOD’s I received for images taken with mine suggest it’s good value for money...
I think your skill in processing might have just as much to do with the APOD's as the scope

Gary
Reply With Quote
  #15  
Old 03-11-2017, 09:39 AM
Camelopardalis's Avatar
Camelopardalis (Dunk)
Drifting from the pole

Camelopardalis is offline
 
Join Date: Feb 2013
Location: Brisbane
Posts: 5,425
I know how much speed counts when it comes to narrowband, so in concert with a faster scope you might want to consider a camera with lower read noise also, since that is the major determining factor in getting sky limited subs.
Reply With Quote
  #16  
Old 03-11-2017, 10:48 AM
AstroApprentice (Jason)
Registered User

AstroApprentice is offline
 
Join Date: Dec 2015
Location: Melbourne, Australia
Posts: 349
Hi Gary,
FYI, with the dedicated reducer/flattener for Borg 71FL or 90FL they are no longer doublets - 6 lens elements in 5 groups.

Atmos: Had a look at Borg whilst on a recent trip to Japan, looked OK but very expensive for doublets that by some reports show a bit of color (short FL?) decided that for that money a Tak might be better :-)
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 06:49 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement