Big Plans, Help Needed!

[miguel87]

So the time has come to make an honest woman of my girlfriend. We both love astronomy, she is a particular fan of the moon.

Since buying 'the ring' i have been looking at ways of proposing. I came across an online story of a guy who managed to write 'will you marry me' on one of his eyepieces, lined it up with a full moon and bam! His proposal was across the lunar surface when his girlfriend looked into the lens!

Do how do i recreate this? Acetate, clear plastuc over the lens with permanent marker pen on? The moon is very bright which will help alot. But would the message even be in focus written on the eyepiece lens?

Please Help!

Mike

[miguel87]

In an ideal world this would be the result. So i need your brain power please!

[John]

You would need to etch or mark the message on a clear material such as glass or acetate and mount that across the focal plane of the eyepiece - where the field stop of the eyepiece is located. It has to be at that position to be in focus.

[miguel87]

Ok great thanks, so somehow dropping it into the barrel up to the field stop. Thats the narrow hole right?

[miguel87]

So on further research it seems the field stop might be between lenses? The eyepiece in question in a plossl, vixen npl.

[michael.h.f.wilkinson]

Depends a bit on the EP design. Plossls, Orthos, Erfles and the like are fine. The NPL should be perfect.

[John]

8 minutes ago, miguel87 said:

So on further research it seems the field stop might be between lenses? The eyepiece in question in a plossl, vixen npl.

With plossls, orthos, kellners and erfles the field stop is located below the last lens, in the eyepiece barrel as Michael says.

You need to pick an eyepiece which will give you a decent image scale of the moon of course. With the 200P, a 10mm eyepiece will show the moon filling the whole field of view.

 

 

[miguel87]

Thanks so much for all the help. Small mistake, i have the slv not npl eyepieces. Might be a little more complex. I will investigate after work today. Might br able to use a barlow to help too perhaps.

[Jimtheslim]

If I were you I would buy a 10mm skywatcher, the cheap ones that people get with the scopes. You can get one for a few quid on ebay. I wouldn't fancy taking apart and inserting things into an expensive eyepiece. Once she see's the message she'll not care too much about the quality of the view. Then you just have to wait for a nice clear night with a full moon when you are both at home!

[Jimtheslim]

And you'll have to be sure to get her up to the eyepiece quickly, without a motorised RA she'll just read "LLURYE?" which will be very confusing for her.

[miguel87]

Haha yeah good point! Ive got the motor working well on the eq5. Buying a cheap eyepiece might be a good idea tho, moon will look great through almost anything.

[John]

Don't open up the SLV's - I'd buy a low cost plossl or similar and use that for this purpose.

 

[Jimtheslim]

or what about a cheap filter, like a dark blue? Not sure if this would work but again you can buy cheap ones for a fiver on ebay

 

[miguel87]

I had thought about the filter idea but i dont think it would come to focus? I could be wrong...

Will look for a cheap plossl, on advice above im looking at 10mm, giving me 100x mag. Im guessin a cheap plossl will have around 40degrees fov. Will i fit the whole moon in this?

[Jimtheslim]

It should just about, however it will be moving quickly. A 25mm would move slower, but of course it would be smaller and the writing would be smaller. If you want to pm me your address I will post you either my old 10mm or 25mm achromat that came with my last scope. 

[miguel87]

Movement should be too much of an issue as my motor works well. I was looking at the stock sky watcher 10mm plossl. I used to have one but sold it when i upgraded. Ok amazing i will pm you. Thanks.

[andrew63]

There's a 10mm plossl for £8 in the for sale section which may do.

Best of luck on both accounts !

 

andrew

[miguel87]

Really greatful for tons of useful responses. I have an eyepiece sorted on its way to me soon. I hought some printable acetate sheets and a super fine marker pen. Think i will only have approx 8mm diameter to work with for the message written on acetate and placed directly over the field stop. Will post some photos as i get to started on the project.

 

Mike

[John]

Whatever you have the inscription on needs to be located at the focal plane of the eyepiece to be in focus when viewed through the eyepiece. Filters, being generally positioned a couple of cm beyond the focal plane, would not be in focus.

 

[saac]

This is such a wonderful idea, it has to work.  Good luck Mike, don't give up on it it will be so memorable.  

 

Jim

[Louis D]

1 hour ago, miguel87 said:

Really greatful for tons of useful responses. I have an eyepiece sorted on its way to me soon. I hought some printable acetate sheets and a super fine marker pen. Think i will only have approx 8mm diameter to work with for the message written on acetate and placed directly over the field stop. Will post some photos as i get to started on the project.

 

Mike

A bit late, but you could have used a 32mm plossl and a 3x barlow ahead of it to get about 26mm of usable diameter.

Do you have access to a laser printer that accepts transparency sheets?  If so, create your design and then scale it down to whatever size you need.  At 300 dpi, it should be somewhat readable.

To locate it at the proper focus point, just push it up against the field stop.  That should be pretty close to correct.

[miguel87]

Did not think of the barlow idea. Might need to consider if i have real trouble with the size of the writing.

Im sure somewhere at my workplace woulf have a laser printer, will test how small ot can print when i get the chance.

Thanks

[miguel87]

So just been messing with the laser printer at work and it prints very small!

 

The top text is 8mm by 7mm and the printer can go smaller!

So if i get some printable clear overhead projector style slides we should be good to go!

[Jimtheslim]

Looks good, but if you go with the above message I think she'll be a bit confused!

[miguel87]

Haha, very true. I started with can you read me? But i wanted the right amount of letters. All top secret stuff going on here!