1.51
#... |
|---|
|
Hello all! Please tell me your experiences with motorizing the WO with a stepper motor! I have a Rigel Nstep on mine and I love it for manual focus but I am having a hard time automating my focusing routine with SGP. Please tell me your stories! |
0.00
#... |
|---|
|
I have the Rigel Nstep for my EdgeHD, and I plan on getting it for the Star71, mostly for cost reasons. But I have found that SGP can be hit or miss when it comes to autofocusing. As you know, hyperstar is really touchy on focus so it is hard to get it just perfect. I end up doing it manually but with the focus motor. It's annoying because I would love to do filter-switch autofocusing to deal with temperture changes. Also, my RGB filters are nowhere close to parfocal with my narrowband ones, so it results in some frustrations. I also have been judging the focus by eye instead of relying on HFR or FWHM statistics, which is causing inaccuracies. Also I need to find a way to set up focus step offsets for my filter sets without having to waste an entire night of imaging to figure it out. Because I have spent all year working with the Star71 (I haven't even hooked up the Hyperstar this year.) I haven't had a chance to work with the Nstep or the routine in SGP in quite a while. |
|
1.51
#... |
|---|
|
Well the good news is that I think I was finally able to get my WO and the Nstep working together on a consistent basis. My autofocus routine is up and running. I also did not figure out offsets but so far I am not needing because my Astrodons are all parfocal. I know what you mean about the Hyperstar, I've had it for almost 2 years and almost never used it. It's always so frustrating and I'm still figuring out colimation I ended up giving up and putting the WO back in the observatory, I know I won't be going outside in the winter to switch filters so I'll probably play with the Hyperstar next summer. If you buy the Nstep for the WO and want me to share the settings, let me know! Take care  |
|
0.00
#... |
|---|
|
I'm using the nStep and the Hyperstar tonight. My only complaint are that I have to run SGP as administrator otherwise it won't connect to the nStep. Probably because windows is stupid, though. The autofocus worked, though it is painfully slow. I won't be setting it to refocus during the session. |
|
0.00
#... |
|---|
| Found out why it was so slow. You have to press the "settings" button and set the steps in there as well as on the main autofocus tab. |
|
1.51
#... |
|---|
| Why do you have to run SGP as administrator to run the NStep? I don't have this issue at all. Neither with Win7 or 10 |
|
0.00
#... |
|---|
|
Odd. I get crazy error messages from the Rigel nStep driver saying it doesn't have access unless I am administrator. But, it is probably because windows is stupid, not the driver. I will have to ask Rigel about this. Once I figured out the step problem the V curve looked really good. Even focusing through narrowband filters was no problem. |
|
1.51
#... |
|---|
| Talk to Leon about it or go on their website and read the instructions again. I remember there was something about this when installing the driver. I followed the instructions and I don't get any error messages at all. |
|
0.00
#... |
|---|
| Good idea. I am about to set up an entirely new computer for astrophotography, so I will rerun the instructions there and see how it goes. |
0.00
#... |
|---|
| I use a Lakeside stepper motor on my WO Star 71. It seems to work extremely well. |
0.00
#... |
|---|
| My intention isn't the highjack this thread, but I have a star71-II and will be using it and my qhy10 in SGP.im new to SGP and was wondering if anyone would mind giving or linking me to some manual focus advice (I don't have a bahlitov mask) but I'm very familiar will live view focus in BYEOS. |
|
1.51
#... |
|---|
Tyler Jackson Welch: Hi Tyler, I highly suggest you read the SGP manual in the part that talks about understanding Autofocus. Basically, you need to start out with good focus, so a Baht mask is a must, Check the HFR on your best focus (write down the position on the focuser), move the focuser OUT about 3-5 times your best focus, write down again your focuser position, subtract your focus position from out of focus - focus, divide that number by 4 (in case you chose 9 steps for the autofocuser) and that will be your step size. So for example in my setup, I check focus with Baht mask, my HFR is 1 and the focuser position 30000, I move OUT until I reach HFR 4, that goes to focuser position 30600, so 30600-30000 = 600 / 4 = 150, that's my step size. I really recommend you real the manual several times, it took me a while to understand the concept here. Good luck and I hope I was able to help. |
|
0.00
#... |
|---|
Tyler Jackson Welch: Tyler My advice regarding manual focus is to buy a Bahtinov mask. |
|
0.00
#... |
|---|
Steve Milne:Tyler Jackson Welch:Tyler Steve, does a bahtinov mask really become more accurate than the HFR statistics in SGP? It seems a mask would get you less accurate because I'd be judging focus with my eye(centering the needle with the mask) where as in BYEOS and SGP a statistical number seems more accurate. But I'm missing something I take it? Thanks for the reply btw |
|
0.00
#... |
|---|
|
When I manually focus with a mask, I use a program called Bahtinov grabber. I'm not sure where you can get this program now though, because the chap who wrote it has (I believe) passed away. But this program gives you 'numbers' that can guide you towards good focus. When I first set up my autofocus routines in SGP, I will check them using the Bahtinov mask and those numbers. SGP gets a good result, but I can get slightly better numbers using the Bahtinov mask and grabber approach. Of course I don't actually know how accurate the mask plus grabber is versus the SGP autofocus routine. I see no reason why you couldn't use HFR - I have seen people using FWMH values on a single star. The downside of a mask, of course, is that you would need to slew off target to find a star bright enough that the mask would work. But SGP's plate solve and centre routine makes this a simple task. I have autofocus on both my imaging scopes. When I didn't have it on one, I would slew to a nearby bright star, use a Bahtinov and then 'Centre' back on my target. It didn't take very long - indeed since you start from being close to focus you probably need less steps than the autofocus routine uses. Sometimes it didn't need adjusting at all, and in those cases it was probably quicker doing it manually than using autofocus. Don't get me wrong - autofocus is great. But running a 9 step autofocus routine using 25 second exposures (because of a 3nm Ha filter), only to find that there is no significant change to the focus position at the end of the routine is a little bit galling. |
|
1.51
#... |
|---|
Steve Milne: I agree with you to a point. When the temperature drops it is a good idea to spend those precious minutes running autofocus, it's better than losing a 30 min exposure. This time of the year for example I am noticing a huge temperature drop from when I start imaging to end of night, I'm talking about starting at around 20 Celsius and close the dome at 3 Celsius. Can you imagine a night of imaging without re-focusing with those temperature changes? No thank you |
|
0.00
#... |
|---|
Samara:Steve Milne:I agree with you to a point. When the temperature drops it is a good idea to spend those precious minutes running autofocus, it's better than losing a 30 min exposure. This time of the year for example I am noticing a huge temperature drop from when I start imaging to end of night, I'm talking about starting at around 20 Celsius and close the dome at 3 Celsius. Can you imagine a night of imaging without re-focusing with those temperature changes? No thank you Samara - if you re-read my whole post you will see that I was not suggesting that at all. When I was manually focussing I checked it every hour and every filter change. Sometimes when I checked it, it didn't need to be adjusted. On those occasions it was probably a quicker process than running the autofocus routine would have been. Regards |
|
0.00
#... |
|---|
| Is there a way to use FWMH in SGP? I only saw HFR in stat window |
|
0.00
#... |
|---|
| Don't think so. The chap I saw doing it this way was using (I think) Nebulosity. I don't know if you could use one of the single HFR values that SGP gives you. |
|
0.00
#... |
|---|
| FWHM is only available in SGP if you have Pinpoint. |
|
1.51
#... |
|---|
Steve Milne:Samara:Samara - if you re-read my whole post you will see that I was not suggesting that at all. When I was manually focussing I checked it every hour and every filter change. Sometimes when I checked it, it didn't need to be adjusted. On those occasions it was probably a quicker process than running the autofocus routine would have been.Steve Milne:I agree with you to a point. When the temperature drops it is a good idea to spend those precious minutes running autofocus, it's better than losing a 30 min exposure. This time of the year for example I am noticing a huge temperature drop from when I start imaging to end of night, I'm talking about starting at around 20 Celsius and close the dome at 3 Celsius. Can you imagine a night of imaging without re-focusing with those temperature changes? No thank you Steve, I understood your post, ues sometimes it is a waste of time to re-focus. Yes, manually checking is very effective but that's what I like about automation, I really like my sleep. If the temperature is stable I can just autofocus on filter change or by temperatuee change. It is not the best thing next to sliced bread like plate solving is but at least to me, it made a huge difference on my images. |
|
0.00
#... |
|---|
|
It sounds like you guys have had a lot more images one with your star71s than myself. I got used to my SCT and how much focus would change with temperature, I'm curious to know what you guys are seeing as far as when its generally worth refocusing? On my SCT the temp could move 5 degreesF and my focus literally didn't need to be touched. What ha w u guys seen with this refractor? |
|
0.00
#... |
|---|
Tyler Jackson Welch: I find it very variable. I have it set so that I autofocus every hour irrespective of temperature change. Sometimes there is a significant change of position, sometimes not. All that is measured is temperature at the telescope, and temperatures elsewhere in the atmosphere may be all over the place. I also refocus between filters. Some folks use filter offsets - I'm not confident that I have mine calculated accurately enough yet. With LRGB it is not much of an issue (5s exposures and 9 steps). With NB, I use 25 sec exposures (I use 3nm filters). It takes longer, but there's not much point having a 20 minute exposure that is not in focus. Everything is binned 2x2 for autofocussing. The key is getting the step size correct. The SGP manual is very good on this - just follow that. Also, pay attention to backlash, by which I mean set a number in there. I use 100 on my WO71, but it depends on your focusser I guess. Hope that helps. |
|
0.00
#... |
|---|
| Thanks for the info Steve! I'm not sure I'll ever go autofocus or not. I'm trying to get used to SGP manual focus by using 2x2 fast mode, and using HFR on both the whole image and choosing a smaller section of area as well. I'm so used to the easy manual focus in BYEOS that this is taking a bit longer to learn and focus nicely. (I'm on a Qhy10 now) I might try nebulosity... I hear the focus tools in there are nice, but I'd hate to drop $200 on two pieces of software, one being used only for focus lol |
|
0.00
#... |
|---|
| No problems Tyler. Having got autofocus, I would not go back to manual. Once it is all set up, you just leave the rig and, weather permitting, a few hours later you have a load of well focussed subs all ready for the difficult part. |
