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Merry Hartmann mask...

The Warthog

By The Warthog
in DIY Astronomer

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The Warthog

The Warthog

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OK so you don't remember the American sitcom, "Mary Hartman, Mary Hartman?" *shakes head sadly* I've made a Hartmann mask. The purpose of this is to aid in focusing a reflector. I don't know if it will work with a frac. When you put it over the end of your scope, and look at a bright star, you will see two stars, which come together as a single, six-pointed star when you get it in perfect focus. Ta-da. I'll try it out first clear night. On Sirius.

I attach stuf like this to the scope by bending the tabs down the tube, and holding it in place with an elastic band.

post-12776-133877318247_thumb.jpg

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Kaptain Klevtsov

Kaptain Klevtsov

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http://www.wodaski.com/newastro/downloads/ccdCalcFree.asp

This, unless I messed it up, is a link to an imaging site with good info on focussing using holy paper plates etc.

I will apologise in advance if this link doesn't work, as I have been creative and copied it from a thread where I asked for advice regarding webcams, and I am not going to click on back 'cos it usually trashes what I've just written.

Captain Chaos

(Must get an avatar, its just so passe not having one)

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The Warthog

The Warthog

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I found that it doesn't do a thing at low power (30x) but at higher power (116x) it gave me two stars when out of focus, and they moved very smoothly into a single star at the focus point. I didn't get the six pointed star effect I had been told about, but when I took the mask off, and pointed at the moon and subsequently at Saturn, focus was tack-sharp.

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Naz

Naz

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saw the mask advertised somewhere on the net for a lot of money, it is great to see that we do not have to spend a lot of money on some bits and pieces to achieve great results.

WH you should put all these ideas and tips that you have found and put them together in a seperate section,

nabban

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  • 3 weeks later...
Albireo380

Albireo380

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Interesting link CC - if you are going to try it, let us know if it works.

I use a 3-hole Hartmann mask to try to sharpen focussing for the DSLR. It seems to work fine on brighter objects (perhaps mag 3 and above). Below that I can't see the object in the viewfinder anyway. But it is fine if I focus using a crescent moon / Jupiter/Saturn as "focus object" and then slew to the dimmer object I want to photograph. Focussing seems to hold okay if I dont slew too far and take too long.

Tom

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The Warthog

The Warthog

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I have used it on a brighter star, like Betelgeuse, and just focus until the two images come together. I doesn't work at lower power (30x) for some reason, but it works well at 114x. It is a bit of a pita to put it on and off while working.

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Albireo380

Albireo380

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Great dogs, Golden Retrievers.

I just magnified up the 'photo WH sent in of his 'scope - is that a Spaniel in the left background?

Is it WH?

Are dogs the keen Astronomer's "must have" accessory for this year?

And yes WH, the Hartmann seems to work best at higher magnification - not sure why = may be something to do with image size / definition. Also, it is a pain to put on / take off when observing - you only need to move the 'scope by one mm to lose the object.

Tom

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radioactive

radioactive

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Great dogs, Golden Retrievers.

I just magnified up the 'photo WH sent in of his 'scope - is that a Spaniel in the left background?

Is it WH?

Are dogs the keen Astronomer's "must have" accessory for this year?

And yes WH, the Hartmann seems to work best at higher magnification - not sure why = may be something to do with image size / definition. Also, it is a pain to put on / take off when observing - you only need to move the 'scope by one mm to lose the object.

Tom

I was thinking the exact same thing about the picture yes cracking detail on the scope and mask but is that a springer or cocker Spaniel I have two dogs and I fear they will knock into too many things when observing at home so unfortunately I could not say wheather or not the actually like stargazing what I know is its always a great welcome back inside :laugh:

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The Warthog

The Warthog

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Great dogs, Golden Retrievers.

I just magnified up the 'photo WH sent in of his 'scope - is that a Spaniel in the left background?

Is it WH?

Are dogs the keen Astronomer's "must have" accessory for this year?

And yes WH, the Hartmann seems to work best at higher magnification - not sure why = may be something to do with image size / definition. Also, it is a pain to put on / take off when observing - you only need to move the 'scope by one mm to lose the object.

Tom

I was thinking the exact same thing about the picture yes cracking detail on the scope and mask but is that a springer or cocker Spaniel I have two dogs and I fear they will knock into too many things when observing at home so unfortunately I could not say wheather or not the actually like stargazing what I know is its always a great welcome back inside :laugh:

It's not me, it's a Welsh Springer, that I refer to as "my retarded Springer Spaniel." She's an absolute love, and great fun to have around. She usually stays out with me when I'm observing, and just sniffs around at everything. She hasn't bumped into anything or chewed anything. She prefers socks for chewing. If she gets bored, she stands on the patio and barks until I let her inside. Then five minutes later, she barks to come outside again.

I'm going to make collars for the masks, instead of the tabs I've been using. That will make them a bother to store, but easier to put on and take off. And will also disturb the scope less when I put them on.

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