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PostPosted: Sat Feb 21, 2015 10:40 am 
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Joined: Sat Feb 21, 2015 10:26 am
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A bit of a newbie question in this department, I have a Skymax 127. If say with a solar filter attached to the front, how safe is is it still to observe the sun. Also what is safe and/or not safe to attach/use on the other end, ie diagonals, lens (own a x2 Barlow, 5mm, 10mm, 25mm and 40mm) and cameras for viewing and imaging. (have a Pentax K-r dslr and a digital camera holder for a smaller camera) thank you.

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Telescope Equipment: Skywatcher Skymax 127 AZ GOTO, 6x30/9x50 Finderscopes, 5mm, 10mm, 25mm and 40mm Eyepieces, x2 Barlow, Pentax K-r DSLR.


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PostPosted: Sat Feb 21, 2015 1:39 pm 
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. Hi there and welcome,
. Great caution is needed.
I think that maybe you should join the SPA solar section, or at least ask your queries there.

Regards, David


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PostPosted: Sat Feb 21, 2015 8:26 pm 
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Joined: Fri Dec 03, 2004 9:58 pm
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Location: Wellingborough
Hi and welcome :)

As David says, great caution is necessary when observing the Sun. A moments inattention or forgetfulness can be disastrous for your eyesight. Health warning over.

Having said that, I use a 102mm refractor for solar observation. I have a full-aperture safety solar filter (made with Baader Astrosolar Safety film) on the front of the telescope. This has an optical density of 5.0, and rejects 99.999% of the incoming solar radiation before it reaches the objective lens. The remaining 0.001% goes on via the standard star diagonal to the eyepiece. I have an IR-cut filter (could be an IR/UV cut filter) attached to the front of the eyepiece to ensure that heat-radiation is totally removed from the image before it reaches my eye.

This approach is now a pretty standard amateur approach to solar observing in white light, with many units worldwide. I made my solar filter myself from Astrosolar film I bought from a well-known astro dealer, but they can be bought ready-made in a range of apertures but at greater expense these days. Don't be tempted to use cheaper aluminised "Mylar" film for solar observation, stick to the proven brands and suppliers.

You will find reports of the solar safety film suffering from pinprick holes after some time in use. It is a wise precaution to hold the filter up to a bright sky and check for pinholes before each use. My experience has been that these filters are remarkably resilient. I made my filter in 2003 and it is still perfect. I store it between observing sessions in a conveniently-sized biscuit tin to protect it :)

I use this setup visually and for imaging with webcams. For imaging I installed an electric focus motor so that I can focus remotely from the telescope, at the monitor screen, and eliminate the wobbles that focusing manually at high magnification can bring.

Regards,

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Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
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PostPosted: Mon Feb 23, 2015 11:17 am 
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Location: Lancashire
As we know there are a number of ways to view the sun with a telescope. Freeman's Mak/Cass 'scope should only be used with a front aperture solar filter/film.
A Mak/Cass isn't suitable for solar viewing by projection or with a Herschel wedge.

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PostPosted: Mon Feb 23, 2015 8:33 pm 
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Joined: Sat Feb 21, 2015 10:26 am
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Thank you for your replies. I had to ask since you do not get a lot of guides that mention MAK Telescopes and wanted to see what is capable and not capable. I am interested in observing and once I feel bit more comfortable try and get some imaging done, but have a digital camera and dslr.

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Telescope Equipment: Skywatcher Skymax 127 AZ GOTO, 6x30/9x50 Finderscopes, 5mm, 10mm, 25mm and 40mm Eyepieces, x2 Barlow, Pentax K-r DSLR.


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PostPosted: Tue Feb 24, 2015 3:11 pm 
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If you pointed your SKYMAX 127 at the Sun, there would be too much heat concentrated on the little aluminised spot on the front corrector; hence the need for a front aperture solar filter.

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PostPosted: Tue Feb 24, 2015 11:10 pm 
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With an aperture solar filter on one end, what mm lens would be recommended? I have a 40, 25, 10 and 5mm.

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Telescope Equipment: Skywatcher Skymax 127 AZ GOTO, 6x30/9x50 Finderscopes, 5mm, 10mm, 25mm and 40mm Eyepieces, x2 Barlow, Pentax K-r DSLR.


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PostPosted: Wed Feb 25, 2015 1:42 pm 
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If you mean which eyepiece to use, it depends on atmospheric conditions. Early morning is often the best time of day for solar viewing, before atmospheric convection
builds up, causing the sun to "wobble".
The best thing is to try out different eyepieces. I often use a zoom eyepiece for solar viewing, for the convenience of being able to rapidly change magnifications ( before the cloud moves in! ).

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PostPosted: Wed Feb 25, 2015 1:53 pm 
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I would think that the 25 mm and 10 mm eyepieces would be best using a recognised safe solar filter, giving respectively 60 times and 150 times magnification approximately.
The 5 mm eyepiece giving 300 times magnification will only really be useful on the best nights for observing Jupiter and Mars, maybe Saturn. Also double stars.

Regards, David


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PostPosted: Sun Mar 01, 2015 12:24 pm 
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Well I have got me the filter for the Front of the Telescope and found so far clouds are just a problem as they are at night! lol. But the basics of the results are good and will post it in the relevant part of the forum soon.

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Telescope Equipment: Skywatcher Skymax 127 AZ GOTO, 6x30/9x50 Finderscopes, 5mm, 10mm, 25mm and 40mm Eyepieces, x2 Barlow, Pentax K-r DSLR.


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PostPosted: Sun Mar 01, 2015 7:57 pm 
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Location: Wellingborough
Just a note to remind you to make sure your findercope is covered - if you have one fitted. A quick flash of sunlight through an optical finder can be very damaging to the eye. I use the 'scopes shadow on the ground to locate the Sun - when aligned the shadow of the tube becomes circular, the length of the tube is not seen.

Regards,

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Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed


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PostPosted: Mon Mar 02, 2015 12:52 pm 
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I just Left the Scope off and used a reflection of light help me find the Sun, I also had to take the diagonal off as I was not getting anything with that connected.

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Telescope Equipment: Skywatcher Skymax 127 AZ GOTO, 6x30/9x50 Finderscopes, 5mm, 10mm, 25mm and 40mm Eyepieces, x2 Barlow, Pentax K-r DSLR.


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