Quick Solar Session : 18 October '22

[+Bino-viewer]

Hi guys,

As we have an eclipse coming up, i'd thought i'd dust off the Herschel wedge and have a practice run with some sun bothering. A beautiful day here in Derby with not a cloud in the sky.

 

It also gave me the chance to try out my new zoom eyepiece on the sun for the first time.

It performed well, although i found using a lower power setting gave the more pleasing views.

 

There was nothing too exciting to see sunspot wise, with 'region 3124' showing close to the limb being the standout group.

 

Not long after i thought i may have some problems with the wedge / scope combo.

After a few minutes of viewing i thought that i could smell something getting overly hot, and sure enough

a finger on the wedge's heat window confirmed it. Not burning hot, but much hotter than i'd seen before

when using my last scope (105mm aperture) which only rendered it 'gently warm'.

I've read the recommended refractor size to use with the HW is 80mm - 120mm approx and anything much bigger 

can cause a heat build up.

This was the first time i'd used my 140mm scope for HW Solar, and i'd kind of taken warnings of using bigger apertures with a grain of salt. Now i know it's an issue, i'll only be having much shorter viewing and imaging runs and make sure the scope is pointed away from the sun at regular intervals to let the wedge cool a bit.

 

I also worry a bit about using an 'oiled triplet optic' for Solar viewing with a HW but TEC assure me this is fine.

 

Anyway, i decided to replace eyepiece with camera and image what i'd seen.

 

  

Heres a couple of images, just prime focus using a Canon EOS R and 2x Powermate (1960mm focal length)

iso 100,  1/320 sec.  Tweaked and cropped using MAC Photos.

Thanks for looking.

 

 

 

[+RonC]

Good start! 

[philjay]

Nice one Rob. You could alway stop it down a bit if it gets too hot. 

[+Bino-viewer]

Thats a good point Phil, i could do that.

 

Or, i could purchase another scope with a smaller aperture....😃

 

I've thought more about it, and i've wondered if there was a build up of dust or small bits of debris on the inside of the wedge's heat window

that started to get hot and burn. I thought at the time i'd glimpsed a very small amount of smoke, that i smelt before realising there were problems....

[+Glafnazur]

Nice one Rob, fingers crossed for the 25th 🤞