First time solar observing

[ONIKKINEN]

Caught the Sun today when it was still over 20 degrees in altitude just now and had a quick look with the Long perng 90mm F/5.5 and a Lunt wedge.

Finding the Sun was not that difficult, i didn't bother coming up with a solar finder but just sighted it with my hand blocking the sunlight so that i dont stare into it. 24mm eyepiece in a 2.5x barlow and found it straight away and already seeing a surprising amount of detail. 1 huge sunspot with a fainter ring around it to the right, and several smaller spots to the left of that. Then i tested how much power is the right amount of power for solar.

I put in a 7mm in the barlow for 180x but this was not great. Quite soft and i felt like i actually saw less than with the 24mm. Same story with an XW10 in the barlow but less worse than the XW7. Then i took the barlow off and found that the 7mm eyepiece giving me 71x was the right power for the job for best detail. Maybe there was a power between 71x and 125x that would have been optimal, but i ran out of glass to test that (XW5?...). Does this sound right that only 71x is what i could get? Sun was at the moment around 25 degrees in altitude and the limb was "breathing" quite heavily, so soupy seeing it seems but never done solar observing before so dont know what to expect in terms of useful magnification.

Then tested my available filters on what works best. I tried a #80A and 25A but these were distracting at best so off they go. Then tried a Baader fringe killer and an ND96 filter separately at first and then together. I found that the best combination for clarity and contrast was the ND96 and fringe killer stacked and kept that in the XW7 for the actual observations. Baader solar continuum would be ideal and i have one on order but dont have it just yet.

Many interesting sunspots of various sizes and shapes were present. The obvious giant one to the right of the center was sort of alone and had nothing obvious next to it. But to the bottom and left of that is a "chain" of sunspots, one resembling the big dipper with Dubhe missing and one shape resembling the Pleiades with a tight grouping of spots. The smaller, uncountable spots dotted around this diagonal chain seemed to breathe a bit with the seeing and i wish i could have gotten a closer look with more power. Many small spots all over that are hard to observe with only 71x, gotta try to catch the Sun earlier in the day next!

Edit:

Actually i just realized that the Lunt wedge has an awful undercut right where the Long perng supplied compression ring clamps it and i can feel it sink in a bit. Its very much possible that that took the scope well out of collimation and it was soft at 125x. I will try with a Baader clicklock adapter next time as it does not seem to sink into the undercut.

Edited July 23, 2022 by ONIKKINEN
Undercuts

[JAC51]

Well come to the world of day time astronomy, really enjoyed reading your account. Your use of filters is interesting, logic of try what you have makes sense and it will be interesting to hear you compare what you have already with the Baader continuum when it arrives. I assume that in addition you are using a ND3? which came with the Lunt? 

Magnification for day time use due to thermals is generally much lower than Night time and in my case in the U.K. while I might have a typical max of x200 at night (130mm refractor) I usual max out at x100 during the day and your x70 would be typical for me. I should add that I’m not an experienced observer and others on this site no doubt can offer more definitive  advice. I have found as you have that seeing is better in the morning, I assume due to fewer thermals before the air heats up.  What I had not realized is during the day how much you can see of your surroundings while using an eyepiece with peripheral vision a towel over the head is my best solution so far. 

 

[ONIKKINEN]

5 minutes ago, JAC51 said:

Well come to the world of day time astronomy, really enjoyed reading your account. Your use of filters is interesting, logic of try what you have makes sense and it will be interesting to hear you compare what you have already with the Baader continuum when it arrives. I assume that in addition you are using a ND3? which came with the Lunt? 

Magnification for day time use due to thermals is generally much lower than Night time and in my case in the U.K. while I might have a typical max of x200 at night (130mm refractor) I usual max out at x100 during the day and your x70 would be typical for me. I should add that I’m not an experienced observer and others on this site no doubt can offer more definitive  advice. I have found as you have that seeing is better in the morning, I assume due to fewer thermals before the air heats up.  What I had not realized is during the day how much you can see of your surroundings while using an eyepiece with peripheral vision a towel over the head is my best solution so far. 

 

My Lunt has a permanently installed ND3 on the bottom of the eyepiece holder so the extra filters were just for comfort only. It seems perfectly safe without any eyepiece side filters installed with a 90mm aperture, but i found that a less bright image was better for detail. For comparison the Moon through my 200mm newtonian is much, much brighter than the Sun was with just the Lunt wedge with an ND3 in it with the 90mm frac.

 I see, i should expect much lower power than nighttime viewing. Good to know! I might have to try some kind of observing shroud as i too was bothered with the surroundings a bit. I tried to cup the eyepiece with my hands to block out as much periphery as possible but it wasn't ideal, and introduces some shake with the AZ5 the scope was on.

[Roy Challen]

I use a semi apo filter with my achro for white light, it's definitely an improvement than without.

100x is also about as far as I go for mags unless the seeing is exceptional.

[ONIKKINEN]

40 minutes ago, Roy Challen said:

I use a semi apo filter with my achro for white light, it's definitely an improvement than without.

100x is also about as far as I go for mags unless the seeing is exceptional.

How do you like the semiapo filter? I was looking at that too but just sort of cointossed towards the fringe killer for no particular reason.

My scope probably should be called a semi-achromat instead of a doublet. It has one Lanthanum element in the doublet objective but no FPL glass or anything so there is residual colour at high powers.

[Roy Challen]

4 minutes ago, ONIKKINEN said:

How do you like the semiapo filter? I was looking at that too but just sort of cointossed towards the fringe killer for no particular reason.

My scope probably should be called a semi-achromat instead of a doublet. It has one Lanthanum element in the doublet objective but no FPL glass or anything so there is residual colour at high powers.

I think it's ok. I use solely with my f/16 achro, just leave it in the diagonal. Between the semi apo, fringe killer and contrast booster filters from Baader, it is the least aggressive, but also has the least colour cast. The contrast booster gives quite a yellow tone. @Chris did a good comparison video on his YouTube channel.

There is still some CA visible on the moon, but for me it's acceptable. Oh, it was cheap too - I bought it second hand.

[JAC51]

14 hours ago, ONIKKINEN said:

My Lunt has a permanently installed ND3 on the bottom of the eyepiece holder so the extra filters were just for comfort only. It seems perfectly safe without any eyepiece side filters installed with a 90mm aperture, but i found that a less bright image was better for detail. For comparison the Moon through my 200mm newtonian is much, much brighter than the Sun was with just the Lunt wedge with an ND3 in it with the 90mm frac.

 

The filters I am using are like you ND3 then solar continuum and that is it for my little Tak FS60 which is my most commonly used scope on the sun. For my 130mm frac I’m finding the combination still a little too bright and have been playing around with adding a single polarising filter as well.  Eyepieces used are mainly Brandon’s and Baader Morpheus.

[Paz]

I find magnification on the sun of around 80x to be reliably available, and about 120x is the most I usually use at home where the local conditions for solar observing are not great due the the heat coming off houses and roads. Usually if I observe solar away from home I can do better than at home. At night observing the moon at home, 120x is reliably available and going over 200x is possible fairly often.

Undercuts are annoying, but these days I only use T2 connections for solar, never 1.25" nosepieces. I use a lacerta wedge that allows T2 at both sides.

[Gonariu]

On 7/23/2022 at 9:23 PM, ONIKKINEN said:

there is residual colour at high powers.

For a couple of months to look at the Sun with my achromatic 80/400, in addition to the necessary sun filter at full aperture, I have been inserting a green W58 filter which, in addition to making the image more contrasted, removes the residual chromatism. I usually observe the Sun at 50X, but when I have time I put 80X, very rarely 100X.