iceman
29-01-2007, 09:40 AM
Hi all
Last night I was finally able to get a first light with my new (second hand) EQ6 + 12" GSO newt. I used the EQ6 with my 10" newt at IISAC2007, and it went well, but hadn't had a chance to use the 12" yet.
I started early yesterday evening, aligning the mount South (including 12° magnetic deviation to the East), so using a digital compass, set it facing 168° and levelled the mount. Once I put the EQ6 head on, the bubble level on the mount indicated it wasn't level!? Don't know why, I left though, and trusted that the tripod was level so the mount should be as well.
Getting the 12" in the rings and balanced was fairly painless.. I need to use 20kg (!) of counterweights to balance the tube, but it seemed nicely balanced afterwards and swung around freely.
Collimating the scope took ages, because a) it was an unfamiliar scope, b) the collimation screws need a screwdriver instead of a hand, c) the centre spot ring on the mirror is a bit too small, d) it's a long way from the eyepiece to the back of the scope ;)
Has anyone replaced the collimation screws on the 12" newts with something that can be done by hand? If so, what/where/how much?
I plugged the fan in and left it running, and went to bed. Got up at midnight to tackle drift aligning, and hopefully image Saturn.
I had no intentions of trying to do any goto or 2-star alignments, I just set tracking to sidereal and used the finderscope to get Saturn in the eyepiece. I noticed some drifting in the eyepiece, but thought I'd try with the CCD just to see if I could get away with only minor adjustments while imaging. I fairly quickly got the image on the CCD (with a bit of luck, I think) using the 5x powermate with the DMK. The first thing I noticed was the increased image scale that the 12" gives over the 10" - exactly the reason why I got the 12" :)
Saturn was drifting way too quickly to image, so I started tackling drift alignment. With no knowledge of how to do it properly, I tried adjusting the latitude and the longitude (azimuth) knobs on the mount, but they didn't make much difference. I now couldn't get Saturn back in the CCD, so ignored that and used the 12.5mm illuminated reticle.
Eventually I found that by physically moving the tripod back to the West (much trial and error), so it pretty much pointed back at South 180°, the drift was almost completely gone.. so a couple of questions arise:
- Why was it drifting when pointing at 168°? If it helps, I think it was drifting in DEC (I had to press "up" on the hand controller to get it back to centre).
- Is there any better knobs for the longitude/azimuth adjustment? With the weight on the mount, it's extremely difficult to tighten it up to make adjustments. My fingers were very sore!
- Is there any better knobs for the latitude adjustment? With the weight on the mount, it's extremely difficult to tighten it up to make adjustments.
- Would a barlow work with the illuminated reticle? The 12.5mm is probably not accurate enough for the long focal length I need.
- Can you get a longer (or not curly) cord between the mount and the hand controller? It doesn't stretch far enough (easily) and wants to keep slinging back when I rest it on the table next to the laptop.
- Can you get a longer (or not curly) cord between the Orion Accufocus unit and the hand controller? It's no-where near long enough when the top of the scope is 2.5m off the ground and the laptop table is 1m off the ground.
- I need new rings, that more easily allow me to rotate the OTA while maintaining balance. The straps are ok, but I reckon they're too dangerous. The eyepiece and RA finder were almost pointing down at times, and made it incredible difficult to get Saturn back in the FOV. Can anyone recommend where I can source some rings that suit a 12" newt? (I can measure the OD tonight unless someone knows it).
Once i'd eliminated most of the drift, I tried putting the CCD back in, but just couldn't get Saturn in the FOV with the 5x powermate. I finally gave up and put in the 2x barlow and got it on the screen easy enough. The seenig just wasn't good enough to do any imaging, and after 2 hours of tackling aligning I gave up, packed up and went to bed.
The weight didn't seem to be too much of an issue, and there didn't seem to be too much (more) vibration when I touched the scope. The Orion Accufocus worked pretty well. I need an illuminated finder like I have on my 10".
All in all, a frustrating night but I learnt a fair bit. No images through the scope yet.. that's the next step (after drift aligning), so I can evaluate the quality of the images compared to my 10", ease of use, vibrations/dampening, image scale/resolution, etc.. that will all help me decide whether to keep the 12" or the 10" (and sell the other).
At the moment it just doesn't feel "comfortable", like it does with my 10".. The 10" is a tube i've had for over 2 years and I know how it works, what it's capable of, it has the good focuser, the temperature sensors, easier to collimate, etc. I'll need to get to the same level of comfort with the 12" before I can properly decide.
Anyway thanks for reading my ramblings, and if you know any of the answers to my questions I'd be most grateful. :)
Some images below.
Last night I was finally able to get a first light with my new (second hand) EQ6 + 12" GSO newt. I used the EQ6 with my 10" newt at IISAC2007, and it went well, but hadn't had a chance to use the 12" yet.
I started early yesterday evening, aligning the mount South (including 12° magnetic deviation to the East), so using a digital compass, set it facing 168° and levelled the mount. Once I put the EQ6 head on, the bubble level on the mount indicated it wasn't level!? Don't know why, I left though, and trusted that the tripod was level so the mount should be as well.
Getting the 12" in the rings and balanced was fairly painless.. I need to use 20kg (!) of counterweights to balance the tube, but it seemed nicely balanced afterwards and swung around freely.
Collimating the scope took ages, because a) it was an unfamiliar scope, b) the collimation screws need a screwdriver instead of a hand, c) the centre spot ring on the mirror is a bit too small, d) it's a long way from the eyepiece to the back of the scope ;)
Has anyone replaced the collimation screws on the 12" newts with something that can be done by hand? If so, what/where/how much?
I plugged the fan in and left it running, and went to bed. Got up at midnight to tackle drift aligning, and hopefully image Saturn.
I had no intentions of trying to do any goto or 2-star alignments, I just set tracking to sidereal and used the finderscope to get Saturn in the eyepiece. I noticed some drifting in the eyepiece, but thought I'd try with the CCD just to see if I could get away with only minor adjustments while imaging. I fairly quickly got the image on the CCD (with a bit of luck, I think) using the 5x powermate with the DMK. The first thing I noticed was the increased image scale that the 12" gives over the 10" - exactly the reason why I got the 12" :)
Saturn was drifting way too quickly to image, so I started tackling drift alignment. With no knowledge of how to do it properly, I tried adjusting the latitude and the longitude (azimuth) knobs on the mount, but they didn't make much difference. I now couldn't get Saturn back in the CCD, so ignored that and used the 12.5mm illuminated reticle.
Eventually I found that by physically moving the tripod back to the West (much trial and error), so it pretty much pointed back at South 180°, the drift was almost completely gone.. so a couple of questions arise:
- Why was it drifting when pointing at 168°? If it helps, I think it was drifting in DEC (I had to press "up" on the hand controller to get it back to centre).
- Is there any better knobs for the longitude/azimuth adjustment? With the weight on the mount, it's extremely difficult to tighten it up to make adjustments. My fingers were very sore!
- Is there any better knobs for the latitude adjustment? With the weight on the mount, it's extremely difficult to tighten it up to make adjustments.
- Would a barlow work with the illuminated reticle? The 12.5mm is probably not accurate enough for the long focal length I need.
- Can you get a longer (or not curly) cord between the mount and the hand controller? It doesn't stretch far enough (easily) and wants to keep slinging back when I rest it on the table next to the laptop.
- Can you get a longer (or not curly) cord between the Orion Accufocus unit and the hand controller? It's no-where near long enough when the top of the scope is 2.5m off the ground and the laptop table is 1m off the ground.
- I need new rings, that more easily allow me to rotate the OTA while maintaining balance. The straps are ok, but I reckon they're too dangerous. The eyepiece and RA finder were almost pointing down at times, and made it incredible difficult to get Saturn back in the FOV. Can anyone recommend where I can source some rings that suit a 12" newt? (I can measure the OD tonight unless someone knows it).
Once i'd eliminated most of the drift, I tried putting the CCD back in, but just couldn't get Saturn in the FOV with the 5x powermate. I finally gave up and put in the 2x barlow and got it on the screen easy enough. The seenig just wasn't good enough to do any imaging, and after 2 hours of tackling aligning I gave up, packed up and went to bed.
The weight didn't seem to be too much of an issue, and there didn't seem to be too much (more) vibration when I touched the scope. The Orion Accufocus worked pretty well. I need an illuminated finder like I have on my 10".
All in all, a frustrating night but I learnt a fair bit. No images through the scope yet.. that's the next step (after drift aligning), so I can evaluate the quality of the images compared to my 10", ease of use, vibrations/dampening, image scale/resolution, etc.. that will all help me decide whether to keep the 12" or the 10" (and sell the other).
At the moment it just doesn't feel "comfortable", like it does with my 10".. The 10" is a tube i've had for over 2 years and I know how it works, what it's capable of, it has the good focuser, the temperature sensors, easier to collimate, etc. I'll need to get to the same level of comfort with the 12" before I can properly decide.
Anyway thanks for reading my ramblings, and if you know any of the answers to my questions I'd be most grateful. :)
Some images below.