Screwdriverone
08-04-2009, 11:26 AM
Hi All,
Just thought I would share my experiences with two pieces of gear that I was "allowed" to buy recently;
The Pentax XF 8.5mm Eyepiece and the GSO Laser Collimator.
Firstly, the Pentax 8.5mm XF (which is designed originally to suit Pentax spotting scopes).
After a poll that I recently posted regarding choices of some sub 10mm eyepieces in the mid price range highlighted some very positive thoughts on the Pentax XF, I decided to buy this EP to complement my current collection.
Its primary purpose was for high contrast views of Saturn and other planets and in this respect, its absolutely AWESOME! Without a barlow, and at 176X mag in my 1500mm scope, there is MORE detail visually on Saturn than I can normally see with the CCD camera and a 2.5x APO barlow!
The stars in a given field are ALL clean and crisp with no hint of coma on my F5 scope all the way to the edge of the FOV. The 20mm eye relief and the superb twist up eyecup, together with the 60 deg FOV make it a pleasure to use.
And don't get me started on the MOON! :eyepop:
With the 2.5x APO barlow and the XF 8.5mm yielding 440x Magification, the details on the crater's rims and objects like the Straight Wall are absolutely stunning with little or no false colour fringing from the barlow being introduced visually. The quality of the SMC coating and the "warmth" of the image are simply superb!
Using this eyepiece with the barlow on Sirius, I was able to, for the first time ever, see Sirius B "the Pup" trailing its searing companion and that was a buzz and a half, let me tell you!
If you have a fast newtonian, or I suspect ANY telescope would suit, then I thoroughly recommend the Pentax XF 8.5mm Eyepiece for only $229. I bought mine from Frontier Optics and it arrived very well packed and in no time flat and Bintel also sell this for the same price. (I have no affiliation with either dealer)
I suspect a lot of the performance from the Pentax XF was also due to the fact that I splashed out ($59 :lol: ) for a laser collimator to try and nail down my collimation on the flex dob.
My decision to by the collapsible 12" has paid dividends as collimation on this scope with a laser collimator is an absolute DODDLE!
First, I put the collimator in the 1.25" adaptor and turned it on. What I noticed straight away was the laser wasn't hitting close to the middle of the secondary mirror. 15 seconds later, the secondary was adjusted to suit the laser spot.
Secondly, a glance down the tube (shielded of course!) showed the secondary wasn't aligned properly to point the laser at the primary mirror centre ring, 20 seconds of allen key work fixed that!
Now, with the laser pointed firmly at the primary centre and the secondary centre, it was time to head down the 1500mm to the bottom of the tube and adjust the primary tilt to point the laser return "up its own path". This is where it gets EVEN easier! Because the secondary mirror is visible from the outside of the tube, the primary return spot on the secondary mirror is quite noticable and can be adjusted extremely easily using the primary mirror screws by looking at the two dots and "homing" the return spot back onto the initial spot coming from the laser. Try doing that with a solid tube!!!
Once the two dots overlapped (or probably more to the point, became ONE dot) a quick check on the 45 deg silvered window on the laser collimator showed the return beam had "scattered" because it had re-entered right into the middle hole on the collimator which indicated it was SPOT ON.
Considering the collimation with a cheshire was WAY out compared to the laser and the fact that EVERY time I needed to collimate, it was a two person process that often took 30-35 mins to get right, the purchase of the laser collimator is probably the most impressive improvement to my arsenal of ever growing accessories to date! TOTAL time to collimate was 4 minutes!
After about 1-2 hours of visual observing the other night (with my mouth agape at the difference in clarity!) I popped the laser back in and did a quick check, noticed it had drifted a bit (due to me not locking the transit screws on the primary enough), so I adjusted it again in 15 seconds and went back to looking through my new eyes again.
All in all, for less than $300 all up, I have now DOUBLED or even tripled my enjoyment levels on the new scope.
Do yourselves a favour and definitely invest in a laser collimator and if the budget allows, I highly recommend the Pentax XF 8.5mm for visual enjoyment in any scope.
(A special thank you to John B (Ausastronomer) and the other friends who contributed a LOT of valuable information to help me select this eyepiece from my poll thread, it just goes to show you how much knowledge is locked within this great website's walls)
Thanks for reading and cheers for now
Chris
Just thought I would share my experiences with two pieces of gear that I was "allowed" to buy recently;
The Pentax XF 8.5mm Eyepiece and the GSO Laser Collimator.
Firstly, the Pentax 8.5mm XF (which is designed originally to suit Pentax spotting scopes).
After a poll that I recently posted regarding choices of some sub 10mm eyepieces in the mid price range highlighted some very positive thoughts on the Pentax XF, I decided to buy this EP to complement my current collection.
Its primary purpose was for high contrast views of Saturn and other planets and in this respect, its absolutely AWESOME! Without a barlow, and at 176X mag in my 1500mm scope, there is MORE detail visually on Saturn than I can normally see with the CCD camera and a 2.5x APO barlow!
The stars in a given field are ALL clean and crisp with no hint of coma on my F5 scope all the way to the edge of the FOV. The 20mm eye relief and the superb twist up eyecup, together with the 60 deg FOV make it a pleasure to use.
And don't get me started on the MOON! :eyepop:
With the 2.5x APO barlow and the XF 8.5mm yielding 440x Magification, the details on the crater's rims and objects like the Straight Wall are absolutely stunning with little or no false colour fringing from the barlow being introduced visually. The quality of the SMC coating and the "warmth" of the image are simply superb!
Using this eyepiece with the barlow on Sirius, I was able to, for the first time ever, see Sirius B "the Pup" trailing its searing companion and that was a buzz and a half, let me tell you!
If you have a fast newtonian, or I suspect ANY telescope would suit, then I thoroughly recommend the Pentax XF 8.5mm Eyepiece for only $229. I bought mine from Frontier Optics and it arrived very well packed and in no time flat and Bintel also sell this for the same price. (I have no affiliation with either dealer)
I suspect a lot of the performance from the Pentax XF was also due to the fact that I splashed out ($59 :lol: ) for a laser collimator to try and nail down my collimation on the flex dob.
My decision to by the collapsible 12" has paid dividends as collimation on this scope with a laser collimator is an absolute DODDLE!
First, I put the collimator in the 1.25" adaptor and turned it on. What I noticed straight away was the laser wasn't hitting close to the middle of the secondary mirror. 15 seconds later, the secondary was adjusted to suit the laser spot.
Secondly, a glance down the tube (shielded of course!) showed the secondary wasn't aligned properly to point the laser at the primary mirror centre ring, 20 seconds of allen key work fixed that!
Now, with the laser pointed firmly at the primary centre and the secondary centre, it was time to head down the 1500mm to the bottom of the tube and adjust the primary tilt to point the laser return "up its own path". This is where it gets EVEN easier! Because the secondary mirror is visible from the outside of the tube, the primary return spot on the secondary mirror is quite noticable and can be adjusted extremely easily using the primary mirror screws by looking at the two dots and "homing" the return spot back onto the initial spot coming from the laser. Try doing that with a solid tube!!!
Once the two dots overlapped (or probably more to the point, became ONE dot) a quick check on the 45 deg silvered window on the laser collimator showed the return beam had "scattered" because it had re-entered right into the middle hole on the collimator which indicated it was SPOT ON.
Considering the collimation with a cheshire was WAY out compared to the laser and the fact that EVERY time I needed to collimate, it was a two person process that often took 30-35 mins to get right, the purchase of the laser collimator is probably the most impressive improvement to my arsenal of ever growing accessories to date! TOTAL time to collimate was 4 minutes!
After about 1-2 hours of visual observing the other night (with my mouth agape at the difference in clarity!) I popped the laser back in and did a quick check, noticed it had drifted a bit (due to me not locking the transit screws on the primary enough), so I adjusted it again in 15 seconds and went back to looking through my new eyes again.
All in all, for less than $300 all up, I have now DOUBLED or even tripled my enjoyment levels on the new scope.
Do yourselves a favour and definitely invest in a laser collimator and if the budget allows, I highly recommend the Pentax XF 8.5mm for visual enjoyment in any scope.
(A special thank you to John B (Ausastronomer) and the other friends who contributed a LOT of valuable information to help me select this eyepiece from my poll thread, it just goes to show you how much knowledge is locked within this great website's walls)
Thanks for reading and cheers for now
Chris