Astrozap Baader Solar Filter

[employee2-4601]

*"Great! It's too *insert suitable expletive here* cloudy to see any stars again!" Lately this seems to have been a very common expression in our household - one advantage of having a relatively small scope is that it's fairly quick to get set up when there is that small break in the clouds. However, I bought a solar filter a few days ago in an effort to get more use out of my equipment. The Astrozap seemed to have very good reviews (purchased from FLO at http://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html) and so I took the plunge.

First off, when it arrived (with FLOs usual swiftness) I was reassured by how well it had been packaged for delivery - OK a mundane point, but nonetheless important. The filters are designed to fit around the OTAs main aperture. Therfore, if you're ordering one for a 130mm scope, then you need the 155-165mm filter. It is secured with three screws, though be careful not to overtighten them. Unpacked, the filter is very solidly-built and comes with a piece of cardboard to protect the front of the filter material (I recommend keeping it for when the filter is being stored).

Luckily on the day it arrived, the sky was crystal clear and the sun was in a good enough position for a first trial (OK, it was about 15.00, so the sun wasn't as high as I would have liked, not to mention the tree next to our garden getting in the way when the wind blew!) The instructions recommend fitting the filter whilst the telescope is not pointed at the sun for obvious safety reasons. Anyway, on to the views!

I have to confess that I didn't know what to expect. However, I was almost jumping up and down with joy at my first sight of the sun. The filter cuts out over 99% of the sun's light and UV, but the view was stunning. With a 25mm EP I could see the whole face of the sun and could even make out a couple of sunspots. On higher magnifications (in my case 12mm and 9mm), it was easier to make out the shape of the sunspots, though there was no granulation or other surface detail - my scope's only a 130mm, so detail is not its strong point. For granulation, I've been informed that you need an EP filter which I intend to purchase next.

Unfortunately, with the sun being so low in the sky, I didn't have long before atmospheric distortion began to affect my view and I decided to take a break.

Is this filter worth the money?

I say a definite yes; you can, if you have money to burn, buy a specialist scope designed for solar observation and I am sure there are definite pros to those models. However, I think that being able to increase the amount of use you get out of a standard OTA is well worth shelling out for the Astrozap. The view I had was inspiring and I am now glued to the daytime weather forcast as much as the night time one.

The obvious thing to bear in mind is that solar observing is not without its risks and these filters will require very careful handling - I've kept all the original packaging that mine came with and handled it as little as possible. The filter uses a dual layer of material so that if there are any pinholes, they will be as unlikely as possible to pose a risk to the observer. Having had my first view of our parent star, I've unlocked an area of astronomy that I hadn't even thought about before and, especially as we approach the summer montha, I look forward to more solar observations - oh and the small matter of the transit of Mercury during May...

[spaceboy]

You will be able to see all white light features on the sun through a 130mm scope. Seeing is as important during the day as it is at night. Granulation benefits from some filtration like the Baader continuim filter but I found this to be a little fussy when using solar film. The next best thing I found was a cheap but often hard to find #58 wrattan filter. I have also been surprised to find that a Baader contrast booster filter good for revealing faculae given that it's not advertised in any way for solar observing.

Filter or no filter if there is haze or a bubbling atmosphere the surface can look a little flat so the best thing is to get out as often as you can and take a note book to take notes as I have also found the suns position in my sky can make a difference.

[Merlin]

We should also bear in mind that there's a layer of clear protective film over the solar film that needs to be removed to get the maximum definition.

[spaceboy]

Ah forgot that. Good call Merlin! There has been no end of people forgot to take the film off.

[Merlin]

The protective film can be a devil to remove, unless a corner of it has already come away to allow us a hold on it to peel back.