8.83
#...
·
·
1
like
|
|---|
| @Eric B. The faster the system the more precision matters and IMO we'll calibrated camera that doesn't move and has the ability to zoom in will always be more accurate than any method that relies on the human eye to detect errors. |
5.61
#...
·
|
|---|
|
Quick question. I plan to get an adapter to try the OCAL (just got it today) with and w/o the corrector. I note most folks use it in the eyepiece holder but threads would be better. OTOH threads would put you much closer to the OTA unless your adapter is moderately long. What, if any, effect would you expect from making the OCAL to focuser distance more or less? |
|
8.83
#...
·
|
|---|
| @Bill McLaughlin my only concern would be that if the OCAL is too close you may not be able to bring the camera into focus at the secondary mirror. I'm not sure what the minimum focus distance is. If you do find that the camera is too close when threaded directly into the focuser it would be easy enough to add spacers between the focuser adapter and the OCAL body. When I finally do make my connection threaded my plan was the use spacers to make the cameras height above the tube the same as it is when it's inserted into the eyepiece to save the guess work. |
|
5.61
#...
·
|
|---|
Reg Pratt: Thanks, sounds like a small set of extensions tubes is in order..... |
|
8.83
#...
·
|
|---|
| Yes, I can't remember if the m42 nose has threads at the end but the body of the OCAL itself is M48 I believe. So all you'd need is an M60 F - M48 M adapter for the focuser and then you can get the camera exactly where you need it. If you want when I get home I can measure the OCALs height above the drawtube to give a reference of where we know for sure the OCAL can focus from secondary to primary. |
|
5.61
#...
·
|
|---|
Reg Pratt: Body has M42 thread but comes with an adapter to M48 (at least the new one does). In my case it has a LEO focuser so would not be quite the same as yours anyway. I ordered an Optec 3000 dovetail (fits the LEO) to M48 adapter as well as an M54 to M48. That will let me try it with and w/o the flattener and fully threaded and still have the ability to move in and out by using more or less M48 extenders. |
|
8.83
#...
·
|
|---|
For those who are using the stock focuser. This is what I'll be getting.  |
1.51
#...
·
|
|---|
|
Helpful tutorial, thanks for posting. Somewhat off topic, but are you sure about the primary mirror being used to adjust the cheshire reflection? I've seen this advised elsewhere but it doesn't seem to work for me with my e-130D. In fact, the Tak manual says just the opposite: the primary adjusts the primary mark and the secondary adjusts the cheshire central reflection. I just recollimated my e-130D for the first time in a while tonight and following the Tak manual worked. Where I did veer from the manual was that I removed the crosshairs entirely once I had the secondary football centered. The crosshairs just seem to create problems, at least when using the stock focuser. I think it's because the stock focuser isn't stable enough. Unfortunately I don't think the OCAL would help in this regard because the problem doesn't seem to be with the Tak tools, but rather with the focuser itself. |
|
8.83
#...
·
|
|---|
| @Dan Yes I am positive. The OCAL behaves differently than the Tak tool so the Tak manual does not apply here. With the OCAL the secondary moves the reflection of the primary mirror. The primary moves the reflection of the cheshire inside the focuser. The exact same behavior is exhibited in this post where I use the OCAL to collimate my other Newtonian. |
|
8.83
#...
·
|
|---|
Bill McLaughlin:Reg Pratt: With the drawtube roughly at the focal plane, its about 60mm from the lip of the focuser to the OCALs M42 F thread.   |
|
5.61
#...
·
|
|---|
|
I got the threaded adapters today and collimated with the flattener in place as the help file suggested. It seemed to go well. I tried it both with the Tak eyepiece holder and the direct thread on. Aside from some differences in initial offset, the results seemed to agree with each other pretty well. The real test will be on the sky tonight...  |
|
8.83
#...
·
|
|---|
| @Bill McLaughlin Awesome! I look forward to seeing your results. |
|
5.61
#...
·
·
1
like
|
|---|
Just got the first images down although not totally dark yet (I was eager to see the results  ). I have to say that it works better than I expected. I will do some more scientific analysis once it gets darker but from what I can see so far it works well to use the OCAL and the flattener in place. I am getting the best stars I have seen yet with this system. Same caveat as Reg, this is with a 2600 so not full frame but that it not recommended with the 130 in any case. Just for clarification, this is also with a LEO and the stack of adapters shown. One (top one) is an adapter that comes with the unit, the other three are ones I got from Agena. OCAL screws directly to the top. |
|
5.61
#...
·
·
2
likes
|
|---|
Better data. ASTAP based on 600 sec Ha image unguided. Still needs tiny tip/tilt adjustment but not much. |
|
8.83
#...
·
|
|---|
| I have a pretty steady hand and I couldn't make small enough movements to get any lower than that 😅 |
|
1.51
#...
·
|
|---|
|
Well, you guys got me. I went ahead and ordered one of these for my e130D. The crosshairs of the Tak tool have always bothered me and I was intrigued by the possibility of replacing them with something more precise. After trying it for a collimation run I have a few questions/comments. - With mine I don't see the end of the drawtube as clearly as you seem to @Reg Pratt . I tried to focus until the edge looked sharp, but I'm not sure if this was correct. - Centering the secondary blot is difficult with this device. It seems to be in focus at the blank edges of the mirror, but when you get near the center it goes completely out of focus. With the Tak tool I don't have this problem. - The advice of the Tak manual and most users of the e130D is to point the scope vertically when adjusting the primary. Whenever I do this I put my light panel flat on top of the front aperture. But with the OCAL, positioning the flat panel this way completely messes up the focus. In fact I couldn't focus at all and had to reposition the flat panel back in its original position, point the scope back horizontally, and refocus. I then adjusted the primary this way, which I've done before and does work, but having it vertical is easier. I can't think of any way to get around this problem with the OCAL other than having it so both the secondary and primary can be adjusted with the scope pointing vertically. - Adjusting the size of the OCAL circles is a little tedious. I can't adjust the sliders precisely so I have to manually type in numbers until I get the circle to be the right size. They should have up and down arrows for this. - Related to the above point about primary collimation, how often do I need to focus the OCAL when collimating? Adjusting focus changes the position of the OCAL markers. While I can readjust to get as close as I can to where the markers were correct, this seems imprecise. |
|
5.61
#...
·
·
2
likes
|
|---|
Dan: I had to put a piece of white paper against the entry from the OTA into the drawtube, and then illuminated that with a flashlight. Then messing with the focus I was able to get the contrast such that I could see the edges of the drawtube so as to set the offsets. NOTE: Edited, I misspoke the first time. |
|
8.83
#...
·
·
1
like
|
|---|
Dan: I've only ever collimated with the scope in park position or horizontal so my light source is always a few inches away from the aperture. I haven't experienced any of the focus issues you described with my v2 or v3. A friend of mine has the v3 as well and described something similar to you in regards to his focus not being as sharp as mine. He emailed OCAL about it and was told the AF motor may be struggling against gravity if the unit is vertical (OTA horizontal). He started positioning the OTA so that the OCAL sat at an angle and that fixed the problem so maybe give that a try. Adjusting the size of the OCAL circles is a little tedious. I can't adjust the sliders precisely so I have to manually type in numbers until I get the circle to be the right size. They should have up and down arrows for this. This can be a little tedious indeed. I wrote down the size all my circles need to be so that I can get where I want quickly. I think you just get faster at it the more you use it. You are correct about the slider being very course but if you click the slider you can then use the arrow keys on your keyboard instead of typing the numbers in manually. Related to the above point about primary collimation, how often do I need to focus the OCAL when collimating? Adjusting focus changes the position of the OCAL markers. While I can readjust to get as close as I can to where the markers were correct, this seems imprecise. I only focus once per location. Drawtube, then secondary, then primary. I can change focus the out of focus circles do appear to drift but when I move focus back there are where I left them. |
|
5.61
#...
·
·
1
like
|
|---|
Reg Pratt: Yes, I did mine horizontal as well. I had an extra female Losmandy clamp and attached that to a board and set that on my table saw for a solid spot to work. Then I also set up my flat panel as a light source. |
|
1.51
#...
·
|
|---|
|
>the AF motor may be struggling against gravity if the unit is vertical (OTA horizontal). I would understand this if the camera was vertical pointing towards the floor but not if it’s just resting on top. |
11.02
#...
·
·
1
like
|
|---|
| Nice work! |
