Need a tip for focusing on the moon

[George Gearless]

I recently bought a Bahtinov mask for both my 80mm refractor and my 180mm Mak. I've found it exceptionaly useful for making a propper focus on stars and nebulae. Particularly for photographing.

Friday, according to weather reports, should offer some clear skies and I might be able to get an hour or so of moonwatching before it sets. With my newly bought planetary/moon camera, I also hope to get some good photos with my Mak 180.

I have only once before had the chance to look at the moon with my 180. And it was a b**ch to focus properly. I suspect it will be even more difficult to focus properly while 'looking' through my camera/laptopscreen.

I don't suppose the Bahtinov mask will be of any use to me in this? So I'm hoping that someone has a tip or two how to go about this. I don't want to waste the limited time the moon is up.

Any hints and tips will be greatly appreciated.

[AKB]

An interesting thread (with some sidetracks, and, indeed some misconceptions by yours truly) here...

 

[cletrac1922]

George

First of all welcome from Land Down Under

I am out a couple of times per month with my club doing presentations in primary schools and scout groups

When observing planets and other DSO objects with my 10" flex Dob, I use either a 15mm or 17mm wide angle eyepiece

When comes to the moon, as lot closer to us, and brighter, I find if use 25mm eyepiece gives you nice view, without cutting off the edge, as happens with 15mm or higher eyepiece

John 

 

[George Gearless]

26 minutes ago, AKB said:

An interesting thread (with some sidetracks, and, indeed some misconceptions by yours truly) here...

 

Thanks AKB. It did actualy help. Shame on me for not doing a propper forum search :).

It seems to be the consensus that if properly focused on a star, it should also be properly focused on the moon. In theory. However, different optical 'illusions' may give the impression of not being in focus over the entire plain. The trick being to find the middleground.

Since I will be using my Mak 180 (and possibly even a barlow to get a good crater shot), I will be looking at a very limited plane. So I am hoping that I can use my Bahtinov mask on a star, and the use the focus on a specific part of the moon that I wish to photograph.

I will revisit this thread when I have some 'hands on experience' to report on the matter.

 

Keeping fingers crossed for the promised clear skies 🤞 on friday.

[George Gearless]

18 minutes ago, cletrac1922 said:

George

First of all welcome from Land Down Under

I am out a couple of times per month with my club doing presentations in primary schools and scout groups

When observing planets and other DSO objects with my 10" flex Dob, I use either a 15mm or 17mm wide angle eyepiece

When comes to the moon, as lot closer to us, and brighter, I find if use 25mm eyepiece gives you nice view, without cutting off the edge, as happens with 15mm or higher eyepiece

John 

 

Thanks John.

My goal is somewhat different than what you describe. I am going to 'stress test' my Mak and new camera to see how close I can get, and still get a useful picture out of it. For this I need to be as precise as I possibly can.

But I readily agree with you that for pure moon gazing (which I will propably never grow tired of) a 20mm or 25mm would grant the best overall view. 

[happy-kat]

Infinity is infinity, focus changes if you change device used as not all devices are parfocal, so if you point to a star and focus and change nothing and point to the Moon it should be ok.

[carastro]

Quote

Infinity is infinity, focus changes if you change device used as not all devices are parfocal, so if you point to a star and focus and change nothing and point to the Moon it should be ok.

Absolutely agree with this.  Focus on a star and then move to the Moon which will be the same focus.

Carole 

[George Gearless]

Disaster!

The moon was too low so I had some houses in the way.  But that's not the disaster. I dropped my Stellarmate and now it doesn't send WiFi signal. I fear it's broken completely. Christmas comming up so I realy can't afford a new one. Argh!

🤬🤬🤬🤬

Until I can afford a new one (or this one magicaly decides to work again), I'm gonna have to go back to basics with unguided photographing with my DSLR.

[happy-kat]

That's a shame, but you don't need to guide for the Moon, so can still play while you try to fix your stellarmate

[George Gearless]

2 hours ago, happy-kat said:

That's a shame, but you don't need to guide for the Moon, so can still play while you try to fix your stellarmate

I operate my camera through Stellarmate (Ekos) too 😩. I'm in the process of looking into if I have the cables required to connect my camera to my tablet/mini-laptop. And even then I have no idea if it'll work. I should be able to fire up K-stars/Ekos that is running on my tablet. Obviously it'll only be able to connect to the camera. But I suppose that'll do for now. IF I can get it to work.

In any case. Not gonna catch the moon for some time anyway because of its position. Or rather the position of my neighbours house. Neither are likely to move to accomodate me :).