Bloke Loc: Waynesboro, Pennsylvania

I was having trouble sleeping last night, so I got up and starting messing around on here. According to Stellarium, the milky way should be up, so I took a wander across the street to my 'local non-dark site". The moon was up, and there were scattered clouds reflecting moonlight, and I couldn't see any trace of our local galaxy at all.

I was thinking about the issue of focus on infinity... With the moon up, no problem. With Venus up, no problem. I just use live view, magnify, twiddle lens till the 'circle' is at its smallest. Looking at normal constellations, however, I can't see *anything* on the screen to focus on.

Now, I can see a cell tower or something pretty much on the horizon, and it has flashing red navigation lights on it. This has to be a couple of miles away, at least. My question is, would this be far enough to qualify as 'infinity' for star photos? Logic says it should, but I want to plumb the wisdom of the ages on here, before wasting a bunch of time taking OOF stars... Maybe that should be wisdom of the sages, I don't know!

If this would work, I can just set my camera up and focus on that before heading off to find somewhere dark to play...

Marc G Loc: East Grinstead, West Sussex, England

Here is something i have got into the habit of doing........
Manually focus when the moon is up & wrap gaffer tape around the focus ring of the lens :)

Oknoder Loc: Western North Dakota

Bloke, I would say yes with the notation that each lens/scope has a different focus point. I can focus on a telephone pole for all my lenses and scopes, except my AT6RC this has a much farther infinity focus point so the pole does not work.

Hope this helps,
Matthew

CraigFair Loc: Santa Maria, CA.

I personalty don't use terrestrial points to get a reliable Infinity Focus.
I find a Star or Planet bright enough to focus my pinpoint on then slew to the object,
snap a few shots to make sure it's in the frame, and begin my series.
Craig

Albuqshutterbug Loc: Albuquerque NM

As do I. Even a little bit off is noticeable with Astrophotography.

JimH123 Loc: Morgan Hill, CA

I'm using Sony, and as I crank up the ISO, I can see plenty of stars to focus on. I purposely avoid the brighter stars since they tend to bloom more and instead pick out a much dimmer star. With focus magnifier on, I can move the viewing window around until I find the perfect star to focus on. I then center it in that window and then switch to an even higher magnification. I then adjust for the smallest diameter.

I wouldn't trust tape to hold it. Even the tiniest touch of the lens changes the focus. It is very, very critical. With stars, you need perfect focus. When off even a tiny amount, your results are very obvious that they are OOF.

Happy focusing!

Bloke Loc: Waynesboro, Pennsylvania

Yeah, but I am not sure I would be able to see any stars on the LCD... Part of the problem is that the parking lot contains 3 street lights. I can shield the camera for taking the photos, but it is hard to make out the screen with any clarity, since there is always glare coming from one direction or another.

Thanks for the input!

Bloke Loc: Waynesboro, Pennsylvania

Does the viewing screen get brighter as you turn up the ISO? I thought that only affected the sensor... If that works, I guess I can just turn it waaaaay up until I find something I can zoom in on to get focused.

Unfortunately, our humidity is on the rise, and most of the time we have bunches of clouds everywhere. Even when there are no clouds, there is so much haze in the air it pretty much destroys any chances.

Next time I cannot sleep, I am going to head out for a drive - I have identified a couple of places which might be better sites, but I need to see them at night to be sure...

Thanks for the input!

CraigFair Loc: Santa Maria, CA.

I know that works on my T2i, so I would expect your 7D & T4i to work the same.
Be sure to turn the ISO back down when ready to shoot.
Craig

Albuqshutterbug Loc: Albuquerque NM

I do the same thing so that I can get a nice focus.
I use a 7D for most of my Astro shots and I usually turn it back down until what I am shooting just barely goes away. I find that is usually pretty close to ball park.

Bloke Loc: Waynesboro, Pennsylvania

Ok, next time I get a decent sky I'll try that out... Unfortunately, looks like we are socked in with wet weather for the next week or so... *sigh*

JimH123 Loc: Morgan Hill, CA

I grew up in Pennsylvania. I know how rare clear nights are. Especially in May/June.

Now living 25 miles south of San Jose, most evenings start out clear, but a few hours after sunset, the clouds roll in from the ocean. This is almost every night. I wonder if these clouds are lower than 4200' Mt Hamilton which is the home of Lick Observatory. I can see it from my driveway, but it is more than a 30mi drive to get there. (Much of that switchback)

Oknoder Loc: Western North Dakota

I am sure that Lick is above the average cloud deck especially if the clouds are regular. You could even get a couple nice wide angle shots with Lick in the foreground. I wonder if the lasers they use as for their adaptive optics are within the visible spectrum, cause that would be a cool effect to capture.

Matthew

Bloke Loc: Waynesboro, Pennsylvania

When I first came to the US, back in 1990, I was working for a while in San Antonio. I met up with a guy who was into astronomy, and went out observing with him many times. He showed me all the planets, except Pluto, but that isn't a planet anymore so that's ok...

We went to visit a friend of his who had built his home around a telescope dome (literally!), on the top of a hill. As we were heading up there, we got caught in a Texas thunderstorm. Really, that should be Thunderstorm, because this was a doosy! The neat thing was, we could see the lightning starting *below* us! The visit was a bust in terms of observing, as he didn't want to risk his electronics by turning everything on while the storm still raged below... Neat trip, though!

JimH123 Loc: Morgan Hill, CA

They now do all their imaging in IR since they are so close to San Jose. I am told that the IR is near immune to light pollution effects. Don't know what freq laser they use. Perhaps my IR modified camera could see it.