Something moved during my night sky shot

[Bigshot]

Hello,

I recently want to learn night photography of the sky. I had my first experience but the results were disappointing. I have a Canon 5D Mark IV with 24-105mm 4L Canon lens. Here are the settings for my photo. Manual mode, exposure 25 s, aperture F4.0, ISO Auto. When I examine my photo (below), I found that something was moving during this long exposure but I have no clue where to look and correct. Can someone help me out? Thanks in advance.

[Bigshot · Accepted solution]

Thanks for the insight. Your image shows uniform streak for the stars but mine is not. Could this due to that your focal length is 150mm and relatively speaking, 15 s is way too long as compared to my 24 mm adn 30 s exposure (using the 500 rule)? As a result, I see dots but you see uniform streak? What was your ISO settimg?

[PhotoGerry]

It looks like a excellent opportunity to photograph Mars just grazing the moon tonight.  Given the brightness of the moon it will be interesting to get the exposure looking right.  Double exposure?

Gerry

[FloridaDrafter]

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@PhotoGerry wrote:

It looks like a excellent opportunity to photograph Mars just grazing the moon tonight.  Given the brightness of the moon it will be interesting to get the exposure looking right.  Double exposure?

Gerry

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I do double exposeres quite a bit, but usually of the full moon with trees in the foreground. Very tricky but worth the time.

I have got some single exposures with Venus, Mars, and a thumbnail Moon in a tight triangle where the dark side of the Moon was lit. pretty awsome.

FD

[PhotoGerry]

I did try Saturn last night along with the Moon and Mars.  What is clear to me is I need to revisit my AF microadjustments on my EF 100-400mm f/4.5-5.6L IS II with the 1.4 extender, and make some tweaks.  Saturn and its rings are pretty tiny to distinquish with a sub 600mm reach. You'd need razor sharp focus to achieve it.

G

[TCampbell]

It is *much* easier to do these shots if you have a tracking head.  I use a Losmandy StarLapse, but Losmandy doesn't make that head anymore (it's basically the right-ascension drive from their GM8 equatorial mount -- used for astronomy -- adapted to fit on a photo tripod and hold a camera instead of holding a telescope.

These days the popular models are either

• Sky Watcher "Star Adventurer" head
• iOptron "Sky Guider Pro" head

Both have good reputation.  Both are rated to hold 11 lbs (5kg).  Both companies *also* make a lightweight version that holds 5.5 lbs (2.5kg) but I don't recommend those ... they seem a bit weak to me and the cost savings isn't worth the frustration.

Expect to spend around $400 USD for one. 

A nice sturdy tripod is also needed.  If you're a passionate photographer, you probably already have one (or more) of those.  I tell people "you want a tripod that is so heavy you'll need to see your chiropracter the next day".  That's an exagerration of course... but the idea gets through.  Cheap lightweight tripods are too wobbly for long exposure shots.

Just a couple of examples of long exposure images done on a tracking head:

The comet is a single 5-minute exposure using a Canon 70-200mm f/2.8L IS USM III at 200mm on a Canon 60Da.

This region in Orion is an HDR with some images as long as 2 minutes, others as short as 3 seconds.  (This is because the Orion nebula has a very bright core but faint outer areas of nebulosity.  An image that captures the faint nebulosity blows out the core.)

This was shot using a Canon 135mm f/2L USM on a Canon 60Da.  The red sensitivity of a Canon 60Da is *much* stronger than a typical camera (it's the 'astrophotography' edition of the 60D).  A typically camera has internal filters which partially block the light to create a camera where the sensor mimics the sensitivity of the human -- so your pictures resemble what you saw.  An astrophotography camera tries to capture as many photons as possible... the internal filter is changed to a IV/IR block filter but it doesn't try to trim the reds down like a traditional digital camera.  It is roughly 4-5 times more sensitive to those red wavelengths than a typical camera.

[ebiggs1]

Your links don't seem to work, Tim.  

[TCampbell]

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@ebiggs1 wrote:

Your links don't seem to work, Tim.  

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I noticed... I dropped the links and replaced them with uploads.  Which is just as well... I noticed some wonky JPEG compression artifacts on my comet photo when I view it on Flickr.  I don't see that on my local copy (but that may be the fault of my Lightroom export settings... I suppose I should double-check those.)

[FloridaDrafter]

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@TCampbell wrote:

This was shot using a Canon 135mm f/2L USM on a Canon 60Da.  The red sensitivity of a Canon 60Da is *much* stronger than a typical camera (it's the 'astrophotography' edition of the 60D).

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I didn't even know that Canon made an astro camera until I read a review of the EOS Ra in Astronomy magazine a few months back. I considered buying it, even though I don't shoot the night sky that often, other than the Moon. I just thought it might make a good low light camera. I liked the idea of using filters in the EF adapter ring. When i do use filters, I use my wifes Cokin system, mainly ND filters.

Thank you for mentioning the 60Da.

FD

[jrhoffman75]

Sequator is a free star stacking software for Windows.

[FloridaDrafter]

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@jrhoffman75 wrote:
Sequator is a free star stacking software for Windows.

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I've looked at several, but you have to convert to TIFF for the free versions. I just don't do it enough to bother with it. I've also found some that will use an AVI. The bottom line for me is you really need a tracking device or the time to align your images in PS or some other stacker, like Sequator. I've tried the "autoalign" feature in some, and it was marginal at best. Not owning PS, I can't comment, so just on the freeware.

[ebiggs1]

Love the Delta plane shot.