Alrediph Delta Cephei the prototype standard candle

Alrediph or Delta Cephei, is the prototype star of the class of  Cepheid variables and located in the constellatioin Cepheid. Its apparent visual magnitude at minimum is 4.34 and at maximum 3.51, changing in a regular cycle of about five days and nine hours. Its variations in brightness is imporatant becayse there’s a relationship between the length of each beat and the star’s brightness. Astronomers can use that relationship to measure the star’s distance. That makes them valuable tools or standard candles for helping to measure the scale of the universe.

Stock 7 and Stock 23

Two pictures of open starclusters Stock 7 (stacked) and Stock 23 (sigle shot).
Stock 7is located near the Heart Nebula and the Fishhead Nebula.
All pictures are taken using refractor TLAPO 80/480 f/6 with Nikon D7500. Stacking was done with DeepSkyStakker and editing with CS4.

Triangulum Galaxy Messier M33

In the constellation Triangulum and on a distance of 3 million light years from Earth the Triangulum Galaxy (Messier M33) can be observed.
This picture is the result of stacking 17 pictures each 30s using Nikon D7500 on TLAOP80/480 f/6. Stacking was done using DeepSkyStacker with pictures of DNG format. Final editing with CS4.

21P Giacobini-Zinner

I'm really satisfied as last night it was finally possible to capture Comet 21P Giacobini-Zinner. The comet was located a couple of degrees south of Messier M37 in constellation Auriga. The picture below is a single shot of 30s using Nikon D7500 on TLAPO80/480 f/6; editing done using CS4.

My new learning applied on Messier M8 Lagoon Nebula

Narrowing RGB for both curves as levels

As mentioned in my earlier blog, narrowing individual RGB for both curves as levels in CS4 gives much better results. Using a stacked picture of Messier M8 Lagoon Nebula shows the difference.

Narrowing only RGB for curves

North America Nebula NGC7000 and Pelican Nebula IC5070

Triggered by Astrometry.net I restacked my pictures of the North America Nebula using DeepSkyStacker. Using CS4 I changed my way of editing the stacked result :

1) slightly sharpen the picture using unsharp mask
2) narrowing each Red, Green and Blue curve
3) narrowing each Red, Green and Blue level

The result is much better then my previous editing and the "head" of the pelican is clearly visible.
The pictures are taken with Nikon D7500 on TALAPO 80/480 f/6. A total of 11 pictures, each 30s with different ISO levels.

Astrometry.net

Astrometry.net

If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then Astrometry.net is for you. Input an image and it will give you back astrometric calibration meta-data, plus lists of known objects falling inside the field of view.

Astrometry.net has built this astrometric calibration service to create correct, standards-compliant astrometric meta-data for every useful astronomical image ever taken, past and future, in any state of archival disarray. They hope this will help organize, annotate and make searchable all the world's astronomical information. (Source Astrometry.net)

Having troubles finding out what I recently photographed my Helios collegue Walter refered towards the website Astrometry.net. After uploading my picture, it took a couple of minutes showing all the details I was looking for. I did some more testing and each time feedback was in short matter of time given of the details of the picture.

You can sign in using your google-account which makes it possible to go back into earlier personal searchs.