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menacegtr    26

High to you all again. It's been a while since i last posted here so i thought i would like to ask you clever people a serious question. I still have my fantastic Startravel 120mm refractor with some very nice upgrades. Anyway, here is what i would like to know. Today i received a solar filter specifically for my telescope, here is the link

https://www.365astronomy.com/Solar-Filter-for-120mm-Refractor-Telescopes.html

What i would like to clarify is, is it safe to just go outside and attach this to my telescope and secure it, i would use cellotape incase wind might blow it off, and also to remove the red dot finder. Is there anything else i need to do before i use this filter. I would appreciate any further advice from you guys. It may have been covered here before but i just want to make sure you all know what i have and its usage

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wookie1965    1,574

Just check there are no pin holes in it by looking through it at a light source obviously not the sun, then yes fit it to the front making sure covers whole aperture and your good to go. I had one on a 150p reflector I took pictures of the Mercury transit. I now have a lunt herschel wedge for my Tal 100rs. 

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laudropb    5,934

You are right to be cautious when it comes to solar observing, but if you make sure the filter is intact with no signs of damage, the whole objective lens is covered by the filter and it is securely fitted you should be safe to go. Always remove any finders as you have said. Just a word of warning. You may find it difficult at first to actually get the sun in the eyepiece. You have to point the scope in the general direction of the sun but do not try to sight along the Telescope tube. Look at the shadow that is cast. You then move the scope until you achieve the smallest shadow that you can get. Hopefully a round shadow. Then look through a low magnification eyepiece and gently scan for the sun. This can be difficult at first but with a bit of practice it does get easier. It took me a few attempts the first time I tried. You can get dedicated solar finders which make life much easier but they can wait as I am sure you will be keen to get your first view. Welcome to solar observing.

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menacegtr    26

Thank you Laudropd for your reply. I am glad its ok to use the filter as intended. Is there any need to worry about the eyepieces, do they need a filter on as well, and is there any worry about destroying my diagonal. As i said in my first  message, there is nothing on the scope that is standard apart from the tube itself, i don't want to ruin any of my kit, or the telescope. Also is it ok to use my 25mm x-cel and the 9mm. Just need all the info i can get

Regards

Dave

Edited by menacegtr
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laudropb    5,934

The image may be very bright. I use a Baader Solar continuum filter, but it is quite expensive. Others use a polarising filter to dim it down a bit. I find the continuum filter gives better contrast, but it does turn the image green lol. I use a zoom eyepiece to find the sun but I use  a 5 mm X-cel for viewing sunspots and it works well.

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Stu    16,513

 

1 hour ago, menacegtr said:

Thank you Laudropd for your reply. I am glad its ok to use the filter as intended. Is there any need to worry about the eyepieces, do they need a filter on as well, and is there any worry about destroying my diagonal. As i said in my first  message, there is nothing on the scope that is standard apart from the tube itself, i don't want to ruin any of my kit, or the telescope. Also is it ok to use my 25mm x-cel and the 9mm. Just need all the info i can get

Regards

Dave

Dave, the filter is ND 5 which is correct for visual and basically reduces the intensity of the sun down to 0.001% of the original brightness and heat, giving an image that is safe to view. It prevents any damage to the inside of your scope, or the diagonals or eyepieces, which is why it is so important it doesn't fall off! So, you are safe to go ahead as described.

As mentioned, various filters can help bring out the detail more. The Continuum is very good, although expensive. An OIII or UHC if you already have them can also be quite effective. Given that your scope is a fast achromatic, you will see CA on the sun so any of these filters will have a good effect in cleaning this up as they have a very narrow frequency band. Note that an ND or variable polarising filter will reduce the brightness but not the CA so I think the others are better options for you.

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menacegtr    26

Thanks for all advice, much appreciated. Would my Baader Semi Apo filter be any good in this situation or do i need the filters you have mentioned

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LukeSkywatcher    8,516

I'd be worried about the Cellotape. I dont think its strong enough or up to the job. On a hot summer day, the glue on Cellotape could melt and the filter may fall off. Its also not very reusable.

Edited by LukeSkywatcher
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menacegtr    26

@LukeSkywatcher Yes i see what you mean. The good thing  about this filter is, it fits snugly inside the dew shield on st120 if that is what you call it

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LukeSkywatcher    8,516

Best not to risk it falling off though. A couple of strips of double sided sticky velcro will hold it in place really well.

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cletrac1922    102

Hi Dave

Provided you have right solar filter should not be an issue

Done same thing with my ED80, and just used electrical tap to secure

Recently purchased a glass solar filter, and fits very snuggly

With my Skywatcher 10" collapsible dob, just remove small hole cover of the lid, and I just attached Baader solar filter underside of the cover, and observe from there

Have attached a couple of pics

One is showing solar filter my ED80

Other is of solar eclipse back in 2012, taken with camera android phone, to eyepiece through my dob

Have fun your solar viewing

John 

 

Skywatcher ED80.jpg

Solar Eclipse.jpg

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LukeSkywatcher    8,516

All good advice above regarding safety. The filter you have is all you will need for observing the Sun in White light. You dont need to invest in solar continuum,polarizing filter etc. 

It blocks out 99.9% of heat, so your scope and eyepieces will be fine.

When you get it, put it in place and start observing.

A couple of yrs ago i bought a white light Hershel wedge (and filters...............400 euro). Love it, but now i want more. I just recently bought a Daystar Quark (1300 euro) because i want to start observing the Sun in H-Alpha.

 

 

Edited by LukeSkywatcher
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menacegtr    26

Thank you to everyone who has commented, i appreciate all your help. I knew i could count on you for advice

10 hours ago, LukeSkywatcher said:

All good advice above regarding safety. The filter you have is all you will need for observing the Sun in White light. You dont need to invest in solar continuum,polarizing filter etc. 

It blocks out 99.9% of heat, so your scope and eyepieces will be fine.

When you get it, put it in place and start observing.

A couple of yrs ago i bought a white light Hershel wedge (and filters...............400 euro). Love it, but now i want more. I just recently bought a Daystar Quark (1300 euro) because i want to start observing the Sun in H-Alpha.

 

 

Regards to you all

Dave

How the hell was you lucky enough to have that user name then

 

Edited by menacegtr

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LukeSkywatcher    8,516
17 hours ago, menacegtr said:

Thank you to everyone who has commented, i appreciate all your help. I knew i could count on you for advice

Regards to you all

Dave

How the hell was you lucky enough to have that user name then

 

I made it up.

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Nyctimene    519

Finding the solar image with the solar filter in place sometimes can be tricky and time-consuming. A solar finder accelerates the process considerably; you can make one yourself:

http://www.dd1us.de/Downloads/a collection of solar finder designs 0v6.pdf

or you can use the solar finder function of the Red Dot Finder Baader Sky Surfer III. Works like a charm - the front tube section casts a shadow, that has to be made congruent with the front end of the rear section; done within a minute:

https://www.baader-planetarium.com/en/accessories/telescope-accessories/finders-and-accessories/baader-sky-surfer-iii-red-dot-finder.html

Stephan

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