sábado, 4 de octubre de 2014

Adventures with a mosaic in Auriga - with a hidden alien

The problem of making nice looking photos (to my own eyes and contact lenses) is that I want to make more photos, extend the field of view a bit more in this or that direction, maybe reach to include the next nice object in the same field of view without losing resolution. There is already a solution to that: mosaics. But nice things come to a price, and in this case the big price is the time and efforts required to build a mosaic. I have done it a few times, not always sucessfully... By the way I need to report here the great mosaic of Orion and Monoceros that my friend Daniel Trueba and myself produced a couple of winters ago...

So far the mosaic of which I was proudest was this one already reported in this blog:

And I'm still quite happy with it. That took me almost 80 hours of exposure. The one I present here “only” 63 hours, but the completion has been much longer. In part due to unexpected issues like a computer crash in which I lost some processed panels, and also a change in telescope. But eventually it came out reasonably well, I believe.

The mosaic contains nine panels in a 3x3 shape. Important details are as follows:

Focal ............. 662.50 mm
Field of view ..... 2d 52' 2.9" x 3d 43' 53.2"
Image center ...... RA: 05 27 49.182 Dec: +34 22 00.83
Image bounds:
top-left ....... RA: 05 35 04.787 Dec: +36 11 35.58
top-right ...... RA: 05 20 52.515 Dec: +36 14 39.36
bottom-left .... RA: 05 34 27.470 Dec: +32 27 57.93
bottom-right ... RA: 05 20 52.294 Dec: +32 30 53.77

This info was obtained after I resolved it with Pixinsight 1.8. The mosaic is in Auriga, and it goes from well known objects like the cluster M38 to the emission nebula IC410 (with the well known “Tadpoles”), plus other less known objects, as seen below in the annotated image. The smaller cluster M36 is just outside teh image to teh left, and the also gamous IC405 is not far to the right. North is up.

Eight out of the nine panels were made with the Takahashi FS102 and the reducer at f/6. Then in spring of 2013, Auriga dissapeared from the sky... In June I changed from the FS102 to the Astro-Physics GT 130, which at f/6 has a focal length of 800mm and therefore a smaller field of view. So in winter of 2013 I took the last, ninth panel, but it was smaller thanb the others. That gave me a lot of headaches. Eventually I managed to attach it to the others, trimming the image a bit (that is when M36 has to be left out).

Obvioulsly the panel is only in H-alpha. Maybe I'll collect some OIII photons, and SII, of part of the image (IC405 for example), but that would be another story. I like it in black and white. This a question of taste... I know that the general public likes to see colors (confirmed by Dave Eicher, editor in chief of the Astronomy magazine during the Starmus 2014 astrophotography course, just one week ago...) but I have been educated in B&W photography and still like its dramatic power.

You can see it also in Astrobin at higher resolution:

Apart from the telescope, already discussed, the rest of the equipment has been the usual one:

QSI 683 camera with Astrodon H-alpha filter, 5nm
Mount ASA DDM60pro, no guiding

Acquired with Maxim DL, Processed with Pixinsight 1.7 and 1.8

Here the annotated image. 

And, hidden in the vast network of hydrogen wisps, an amazing creature is hidden, like an abisal fish. Below there is a detail of it. Can you find it in the large picture?

1 comentario:

  1. Pedazo de fotos Jesus... la verdad admirable trabajo, saludos Miquelin... desde los DuPonters del edificio W.

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