Atmos
18-04-2016, 10:52 PM
Well I have had my new Sky Rover 130mm Sextuplet Astrograph out a couple of times so far, not that the first time really counts! It had its first moments up at the Tak Attack party where I hoped someone may have a super ultra short diagonal for an eye piece to come into focus, being an astrograph I didn’t have my hopes up and, as was expected, it wasn’t used.
Moving to more recent times, I had it out both Saturday and Sunday nights. Starting with Saturday, I headed up to Heathcote (one of the few places in Vic where it wasn’t supposed to be cloudy) with a 70% moon but I had to contend with 35km/h winds or a portable setup… Needless to say, the sky conditions sucked. I had my 12” dob out for a few hours, most of the time it was seriously difficult to even spot the GRS on Jupiter, I did have a few fleeting “magic" moments where not only the GRS was clearly visible but nice band detail. The sky conditions weren’t even good enough to see the Cassini Division on Saturn 99% of the time.
The first two images are 60x50s R&G and 13x50s B (with cloud increasing and eventually being forced to stop) of NGC 5128.
On the Sunday night I was imaging from my house, no wind! The third image is 4x900s of NGC 3584 in Ha. I also got 1x900s HaOIIISII on M16 but I haven’t really looked at it yet.
So, the scope itself! My thoughts so far is that I am very happy with it. What I have learned is that the distance from the rear lens cell (inside the focuser) to the CCD has a direct impact on how much the focuser has to be racked out to come into focus. When I was originally doing my calculations I didn’t think that all of my current adapters would allow me to achieve focus with my setup. Back of the envelope calculations put me needing 7mm more inwards travel.
So I had ordered a M68 to M48 adapter which shaved off 15-20mm. This is what I used on Saturday night and in doing so I racked the focuser out 50mm to achieve focus. This left me with a focal length of 695mm, and, as CCDInspector told me later, a bucket load of tilt. Should have expected that aye :P
On Saturday I used the original M68 to M48 adapters just to see if focus could be achieved. I was a bit surprised but I only needed to rack it out 15mm (better than needing more inwards travel) and with a resulting FL of 665mm.
What I learned is that having a longer more rigid distance between the end threads on the focuser and the CCD is better. It results in a more imaging train BUT it reduces the FL (faster imaging).
On the telescope itself, it is solidly built and feels hefty… Although not quite as hefty as a TOA-130! Only has a 2.5” focuser as opposed to a 4”. The focuser is smooth and I have not any any issues with slippage or lifting a QHY22+CFW. This may not be the heaviest imaging train but I also haven’t tightened the locking screw yet so it could take a lot more. Cris has also informed me that three screws on the focuser can work as a camera angle adjuster so that is something that I should look at playing with in the future if need be.
I have found this refractor easier to balance than the previous Sky Rover 130mm I had, this is largely likely to be due to having a rear triplet lens element to add weight to the non-primary lens end.
The only problem that I have had so far, if I could call is a problem, is that the dew shield is very snug! It has 1” long woolen strips that it slides against around the lens assembly, this is for protection but at the moment this makes it more difficult to move it. One plus side to this is that I have no need to lock the dew shield :P Always look on the bright side of life :lol:
Although I have a little more testing I’d like to do on finding out whether there is an “optimal” distance from rear lens element to CCD, it works well regardless. Always about trying to get the absolute most out of it right ;) I am more than happy with the new purchase, need to fiddle with the focuser angle adjuster to see whether I can reduce that 3% tilt down further :P
One test I want to do next new moon is put my D700 (full frame) and see how it goes with edge correction. The QHY22 has 95% illumination but it really is a pretty small chip!
Moving to more recent times, I had it out both Saturday and Sunday nights. Starting with Saturday, I headed up to Heathcote (one of the few places in Vic where it wasn’t supposed to be cloudy) with a 70% moon but I had to contend with 35km/h winds or a portable setup… Needless to say, the sky conditions sucked. I had my 12” dob out for a few hours, most of the time it was seriously difficult to even spot the GRS on Jupiter, I did have a few fleeting “magic" moments where not only the GRS was clearly visible but nice band detail. The sky conditions weren’t even good enough to see the Cassini Division on Saturn 99% of the time.
The first two images are 60x50s R&G and 13x50s B (with cloud increasing and eventually being forced to stop) of NGC 5128.
On the Sunday night I was imaging from my house, no wind! The third image is 4x900s of NGC 3584 in Ha. I also got 1x900s HaOIIISII on M16 but I haven’t really looked at it yet.
So, the scope itself! My thoughts so far is that I am very happy with it. What I have learned is that the distance from the rear lens cell (inside the focuser) to the CCD has a direct impact on how much the focuser has to be racked out to come into focus. When I was originally doing my calculations I didn’t think that all of my current adapters would allow me to achieve focus with my setup. Back of the envelope calculations put me needing 7mm more inwards travel.
So I had ordered a M68 to M48 adapter which shaved off 15-20mm. This is what I used on Saturday night and in doing so I racked the focuser out 50mm to achieve focus. This left me with a focal length of 695mm, and, as CCDInspector told me later, a bucket load of tilt. Should have expected that aye :P
On Saturday I used the original M68 to M48 adapters just to see if focus could be achieved. I was a bit surprised but I only needed to rack it out 15mm (better than needing more inwards travel) and with a resulting FL of 665mm.
What I learned is that having a longer more rigid distance between the end threads on the focuser and the CCD is better. It results in a more imaging train BUT it reduces the FL (faster imaging).
On the telescope itself, it is solidly built and feels hefty… Although not quite as hefty as a TOA-130! Only has a 2.5” focuser as opposed to a 4”. The focuser is smooth and I have not any any issues with slippage or lifting a QHY22+CFW. This may not be the heaviest imaging train but I also haven’t tightened the locking screw yet so it could take a lot more. Cris has also informed me that three screws on the focuser can work as a camera angle adjuster so that is something that I should look at playing with in the future if need be.
I have found this refractor easier to balance than the previous Sky Rover 130mm I had, this is largely likely to be due to having a rear triplet lens element to add weight to the non-primary lens end.
The only problem that I have had so far, if I could call is a problem, is that the dew shield is very snug! It has 1” long woolen strips that it slides against around the lens assembly, this is for protection but at the moment this makes it more difficult to move it. One plus side to this is that I have no need to lock the dew shield :P Always look on the bright side of life :lol:
Although I have a little more testing I’d like to do on finding out whether there is an “optimal” distance from rear lens element to CCD, it works well regardless. Always about trying to get the absolute most out of it right ;) I am more than happy with the new purchase, need to fiddle with the focuser angle adjuster to see whether I can reduce that 3% tilt down further :P
One test I want to do next new moon is put my D700 (full frame) and see how it goes with edge correction. The QHY22 has 95% illumination but it really is a pretty small chip!