I know next to nothing about Solar imaging.
Im chuffed with my new PST, id like to image with it.
Ive searched IIS and find quite a bit of info on solar imaging, PST and suitable cams.
So, Im thinking a DSLR (or an ST10?), some pics ive seen are quite good or a DMK31, nice res and still get 30fps. I understand the 41 is a bit slow (fps), and I think the 21 is fast but a bit low res. Cant see colour version is of much use with the sun or moon, but then would be handy for planetary (although for that the lower QE would count I guess). I dont see a filterwheel for mono DMKs, so thats a bother. Is a colour DMK any disadvantage for sun or moon?, or should I stick with mono, even just for sun and moon only?.
Ive seen the backfocus issue, ill get round that.
Im not keen to spend huge amounts of readys yet (but forget webbies), all I want to start with is this kind of result Peter Ward also did with cheap gear.
I'm more than happy with the results from the DMK41.
I use 1/120s exposures for the surface an 1/20 to 1/11s for proms.
The frame rate is not really an issue.
As we are working in monochromatic Ha light - a colour camera is totally unecessary and gives poorer results.
I'm more than happy with the results from the DMK41.
I use 1/120s exposures for the surface an 1/20 to 1/11s for proms.
The frame rate is not really an issue.
As we are working in monochromatic Ha light - a colour camera is totally unecessary and gives poorer results.
Hi
There have been some interesting comments on solar imaging with a PST but how many have actually tried it.
I have a PST and they are great as an entry telescope for solar viewing and with a suitable eyepiece much can be seen.
However imaging is a different problem. The first thing needed is to mount the PST on a stable platform that can track the sun. The sun moves accross the sky at its solar rate not sidereal so your tracking rate needs to be set to this. As exposures are going to be short the movement during exposure won't be noticed and guiding not necessary but for multiple exposures and mosaics you will need to keep the sun in the picture.
The next problem is the camera to be used. I tried my basic set up with an LPI. Why because it was available. The big problem now was the laptop that I was using. Have you ever tried to use a laptop in bright sunlight while you try to manually focus and frame. Even with a shielded enclosure it was still near impossilble to do this accurately.
Have you ever tried to do a two star alignment or a polar alignment on a mount during daylight. My mount does not track the sun (autostar controlled), it won't even let you look at the sun so I needed to write a little program to make it track the sun. This needed a second computer. My polar alignment was only within about two degrees.
By the time I had got a prominence tuned and in focus I managed about three frames before the clouds rolled in. I haven't tried again since
When I get another chance to do some imaging I will need to have solved all the above problems. (and get the PST back from my grandson who does not want to part with it).
Barry
Last edited by Barrykgerdes; 17-08-2011 at 09:20 AM.
I used the PST mounted on a basic single RA drive EQ2
A small dovetail held the PST, rough "polar" alignment and a bit of "fine" tuning using the drift of the suns image.
Std sidereal tracking rate
Worked 100%
Now I have a HEQ5pro set up for solar with a dual bar, so I can have either the double stack SM60, 88mm modded PST or the SM60/PST double stack alongside a 100 f5 Baader white light scope.
I use a small table, 60 litre grey plastic tub, with the lid hinged with gaffa tape to hold the laptop and an ol' dark sheet thrown over to keep out the light.
Worked well for the last five years.
(The attached image shows the double stcked SM60 on the ED80/EQ2 and the Vegemite controller)
HTH
The PST has the solar finder built in. I know where the Sun is, I don't need GOTO to make my mount find it for me so I don't need any 2-star alignment.
Even sidereal rate is close enough for tracking the sun, especially at the short focal lengths normally used for solar imaging. The hand controller satisfies the need to re-center.
The PST has the solar finder built in. I know where the Sun is, I don't need GOTO to make my mount find it for me so I don't need any 2-star alignment.
Even sidereal rate is close enough for tracking the sun, especially at the short focal lengths normally used for solar imaging. The hand controller satisfies the need to re-center.
Hi Mike
Wait till you try it.
For visual use finding, focusing, tuning and tracking the sun is no bother.
I thought the same as you till I tried it. You can't keep the sun in view manually and photograph it at the same time. You don't need a goto but you do need to track automatically.
I got out my old autostar mount and made adaptors for the PST. Did a fake alignment that would have been good enough to track the stars but it was no good for the sun that slipped out of view in a couple of minutes. That is why I needed to write a tracking program. I could not see the computer screen in the daylight so I next had to build a shielded enclosure.
My original aim was to take a series of time lapsed shots and make a movie of the prominences. I never got that far before I had to pack up after spending about 3 hours getting around the basic problems.
So if you want to take serious photos you will need to align your mount and track the Sun
I now have a HEQ5 pro and a program to track the sun and a much better shielded enclosure so my next attempt will be a little more sophisticated. My point is that the PST is a nice little scope for solar viewing but if you want "professional" results you need a "professional approach"
My current Mac laptop is bright enough in full sun thankfully, my old one certainly wasn't!
Do any of the laptop based guiding programs allow the EQ6 to track the sun correctly?
Quote:
Originally Posted by Barrykgerdes
Hi
There have been some interesting comments on solar imaging with a PST but how many have actually tried it.
I have a PST and they are great as an entry telescope for solar viewing and with a suitable eyepiece much can be seen.
However imaging is a different problem. The first thing needed is to mount the PST on a stable platform that can track the sun. The sun moves accross the sky at its solar rate not sidereal so your tracking rate needs to be set to this. As exposures are going to be short the movement during exposure won't be noticed and guiding not necessary but for multiple exposures and mosaics you will need to keep the sun in the picture.
The next problem is the camera to be used. I tried my basic set up with an LPI. Why because it was available. The big problem now was the laptop that I was using. Have you ever tried to use a laptop in bright sunlight while you try to manually focus and frame. Even with a shielded enclosure it was still near impossilble to do this accurately.
Have you ever tried to do a two star alignment or a polar alignment on a mount during daylight. My mount does not track the sun (autostar controlled), it won't even let you look at the sun so I needed to write a little program to make it track the sun. This needed a second computer. My polar alignment was only within about two degrees.
By the time I had got a prominence tuned and in focus I managed about three frames before the clouds rolled in. I haven't tried again since
When I get another chance to do some imaging I will need to have solved all the above problems. (and get the PST back from my grandson who does not want to part with it).
Perhaps I ought to dispell a few things being said here.
I have imaged with the PST years ago before I got my solarmax60.
You can image easily with this little scope. You need to cut down the nose cone of the adapter on a monochrome camera. Forget using a DSLR. This is monochrome light so monochrome imaging gives sharp results. The bayer matrix on a DSLR will kill the image for detail. Besides the camera will weight too much and rotate.
Next using a blanket or towel over a box is great for seeing the image on the Laptop screen. I do this everytime I image and it is no drama.
Like Mike said sidereal is fine for imaging and you have to be a long way out of PA for the image to drift quickly. I use solar rate myself but it can be done with a quick setdown and using a compass to find PA.
You don't need to do a 2 star alignment. Nearly every mount has a free tracking rate that does not require an alignment. Just set it down and get it tracking.
As for images here is one. And another and another. Each were taken with a 2.5x barlow which easily reached focus. Just make sure you can reach the etalon and the focusor and you can have your head under the blanket.
Peter. Yes, well all the stuff you mention ive looked at, all very good ofcourse, but all a bit pricey at this stage. Ill see if im any good at it 1st with lesser gear.
Greg. Those links look promising, it looks like a DSLR is certainly an option.
Andrew. mmmm, it is a bit WW isnt it. Still, its a different sort of experience, so I hope to get away with it without loosing what little credibility I have ;-).
Mike. If youve got a DMK41 too, then thatll extra do me. Eclipses sound like fun with it all too.
Barry. Youve bought up some interesting topics there. Ive been wondering how to track the sun. I dont even know if the PME has a solar rate. Perhaps I can roughly guide on it with a filter on the guide scope at sidereal . Ill see if I can set the speed on my Timemachine to track the sun on an EQ3. Yes, a lappy in full sun isnt flash.
.
