Dutch Deep Sky

Barnard's Loop

2012-01-31T23:29:00.002+01:00

Recently a friend of mine made an adapter for me that enables me to fit my "old" Mamiya 645 medium format lenses on my "modern" ST-8300M CCD-camera. Because of the large flange focal distance of the Mamiya 645 lenses, there remains enough space to fit a filter wheel between the lens and the camera.

On the evening of January 31, 2012, I've tried out the adapter and it works! The adapter has been made a little shorter than calculated to be sure that the lenses can be focused in combination with filters in the light path. Instead of rotating the lens to the infinity mark, the lens has to be focused on a bright star (or object on the horizon).

First light was with a 45 mm f/2.8 lens and 7 nm H-alpha filter. The camera and lens were mounted on my Vixen Photoguider.

I took 12 images of 5 minutes each (unguided and rough polar alignment). Two images were wasted due to guiding errors, so here is 50 minutes of Barnard's Loop in Sweet Lake City's light pollution soup.

City Astronomy

2012-01-28T13:47:00.002+01:00

Dutch Astronaut André Kuipers took an image of the Netherlands (and Belgium) from space.

I live in the centre of the red cross hair: one of the most light polluted areas of the Netherlands. The bright yellow spots are caused by assimilation lights of greenhouses.

What does this mean for (amateur) astronomy? Well, kids who grow up in this part of the Netherlands cannot experience the splendour of the milky way. Most kids don't even know the existence of it, until they go on a holiday to a "dark" place. It also means that taking a picture of the Orion constellation with an exposure time of 2 minutes will lead to an overexposed image. The image below was exposed for 10 seconds at ISO 1600 with a Canon 5D Mark II and Canon EF 24-70 mm f/2.8 L USM lens at 25 mm f/5.6.

The only celestial objects in the sky that don't get disturbed by light pollution are the moon and planets. The following picture was taken on the same evening (January 27, 2012) at the public astronomical observatory of Rijswijk, located on top of a 12 storey high apartment building. You can see Jupiter on the top left and the moon and Venus at the lower right. On the foreground, a fellow astronomer is taking pictures of this conjunction. The high antennas are lightning rods. Exposed for 2.5 seconds with the same camera and lens at 24 mm f/5.6 and ISO 1600.

When the moon set, it disappeared in the clouds. Again taken with the same camera, but with a Mamiya 210 mm Sekor-C f/4 lens. Exposed for 4 seconds at f/8 and ISO 1600.

Ten years of astrophotography

2011-12-26T23:19:00.008+01:00

We are reaching the end of 2011. Coming to think of it, it has been 10 years when I took my first serious astrophotograph.

At lot has changed since. Let me try to illustrate the differences between now and then.

In 2001 I ...
... had to use finder charts for finding and framing my targets.
... had to use a knife-edge for focusing.
... had to manually guide my telescope.

... wished for an autoguider.
... had to be awake while exposing my targets.
... would often fell asleep while exposing my targets.
... had to expose for 1 hour straight in order to get a decent image.
... had to wait at least a day to develop the film and see the results - Argh!

... started getting bald.
... had to leave home and go to a dark place to see the milky way.
... wished for a bigger telescope.

In 2011 I ...
... could point my telescope to any of several thousand of targets with a goto system.
... could autofocus my telescope.
... could autoguide my telescope.

... wished for an autoguider that wouldn't fail.

... could go to bed while exposing my targets.
... would often be awake while exposing my targets.
... could expose 60x 1 minute in order to get a decent image.
... could see my results directly on a monitor.
... started getting even balder.
... had to leave home and go to a dark place to see the milky way.
... wished for a bigger telescope.

As you can see, some things never change.

Aurora Borealis

2011-12-26T21:27:00.013+01:00

Friday, April 13, 2001 didn't bring bad luck to me: it was the first time I witnessed the Aurora Borealis or Northern Lights. Well, actually it was the second time. The first time I observed it, on April 6, 2000, I had mistaken it for noctilucent clouds.....

On Aril 10, 2011, a massive coronal mass ejection (CME) occured.

Because of this CME, observers were advised to watch out for the Northern Lights. I decided to go to the Wassenaarse Slag - a car park on the coast of The Netherlands, just north of The Hague.

I met two other observers on the Wassenaarse Slag: Richard Francis and Hugeutte Sawaya who work at the European Space Research and Technology Centre (ESTEC) in Noordwijk. They weren't aware of the fact that tonight it was possible to witness the Aurora. In fact they had brought a Meade 8-inch LX90 telescope with them for some casual observing of deepsky objects.

Around 21h30 UT, a strange cirrus cloud became visible above the sea. The cloud became larger and looked like a curtain: we were witnessing the Aurora Borealis! I had loaded my Olympus OM1 camera with Kodak RF1000 colour negative film. I managed to take two shots of 1 minute with a 50 mm lens (probably at f/4, I didn't recorded that).

I've scanned the film and with a few click in Photoshop CS5 I managed to merge to pictures to a panorama.

The clouds have an odd green colour. To the eye the Aurora was, indeed, green instead of the pink and blue colours seen in the pictures.

One of the things on my wish list is to visit the Lofoten islands of Norway to witness the full splendour of the Northern Lights and to capture it with modern photographic equipment.

From the archives: Moon and Venus conjunctions

2011-12-21T21:50:00.003+01:00

According to me, one of the most beautiful sights in astronomy is to see the Moon together with one or more planets in the twilight sky. It gives a feeling of depth when these celestial bodies group together.

After browsing through my image files, I found two images that depict the Moon in conjunction with Venus. I've never published these pictures on my website, so now I share them with you in my blog. Please click on the images to view them at a higher resolution without JPEG artifacts.

The first picture was taken on April 16, 2010, 20h33 local time. The picture was taken with an Olympus E-500 with a 40-150 lens operating at 92 mm f/7.1. The exposure time was 0.5 seconds at ISO 400. (Thank you, Exif data!)

The second picture was taken on December 31, 2010, 7h31 local time. Same camera, same lens, but operating at 55 mm f/7.1. Exposed for 5 seconds at ISO 200.

Clouded out: lunar eclipse

2011-12-14T23:28:00.006+01:00

On December 10, 2011 a lunar eclipse occurred. In the Netherlands, the partial eclipsed Moon raised around 16h30 local time above the horizon. To witness this event, a clear sight on the north-eastern horizon was necessary. Therefore I decided to go to the public observatory of Rijswijk that is situated at the 13th floor of an apartment building.

I witnessed the Moon raising above the horizon, but soon after that, it disappeared behind the clouds. I did however manage to capture an interesting conjunction of the Moon and Saturn.

Did you know that when you live in the Netherlands, you live in one of the most light polluted areas on Earth? Look how much light the clouds reflect in the following picture. The bright "star" in this image is planet Jupiter.

First post

2011-12-14T22:58:00.002+01:00

Today I decided to start a blog as an interactive extension of my personal website. On this blog I will share my astronomical adventures.

As a kick off I would like to share one of my timelapse experiments with you. This timelapse has been made at the public observatory of Rijswijk with a Canon 5D Mark II and Canon EF 24-70 mm f/2.8 L USM lens at 24 mm f/4.5 and ISO 800.

Not a very spectacular timelapse, but I need to practise for my trip to La Palma this winter. For this trip I recently acquired a second hand modified Vixen Photoguider. This is a small equatorial tracking mount on which two cameras (or a camera and a guidescope) can be mounted. It enables me to track the stars and compensate for the Earth's rotation.