Vaonis Vespera - Further Observations with the Dual Band Filter

Introduction | Walking Pattern Noise with the Dual Band Filter | Photos with and without Dual Band Filter | First Conclusions | Links

On this page, I describe further experiences with my electronic 2" refractor telescope Vaonis Vespera 50 mm/200 mm (f/4) when observing with the Dual Band Filter.

See also pages:

Introduction

On this page, I take a look at Walking Pattern Noise when using the Dual Band Filter. And I also compare some nebula photos that were taken without and with the Dual Band Filter.

Photos: My Vaonis Vespera (end of July 2022)

Dual Band Filter


Dual Band Filter		Dual Band Filter

Walking Pattern Noise with the Dual Band Filter

When I photographed the nebula NGC 281 (Pacman Nebula) in January 2024, I noticed that the photo showed clear walking pattern noise when photographed "normally". I therefore aborted the observation and repeated it as a mosaic, because mosaics use simple dithering, which reduces (or eliminates) the WP noise. I had also noticed this during an early observation of NGC 2174 (Monkey Head Nebula), which I present here again, but I had not pursued this phenomenon any further at the time...

NGC 2174 (Monkey Head Nebula)

The following images of the Monkey Head Nebula were taken in April 2023 without and with filters in "normal" mode:


NGC 2174, Apr 5, 2023 - original, 35min		NGC 2174, Apr 5, 2023 - large, photo left processed

NGC 2174, Apr 5, 2023 - original, CLS Filter, 35min		NGC 2174, Apr 5, 2023 - large, photo left processed

NGC 2174, Apr 5, 2023 - original, Dual Band Filter, 35min		NGC 2174, Apr 5, 2023 - large, photo left processed

Here you can see that the WP noise is strongest with the Dual Band Filter; in this example it is lower with the CLS Filter and lowest without any filter. Unfortunately, this early example lacks a mosaic image that could show how much the noise is reduced by the mosaic mode. However, I can "supply" this information with images from January 2024!

I also find it interesting that all the photos turned out almost equally bright with the same exposure time. The photo with the Dual Band Filter is even the brightest...

NGC 281 (Pacman Nebula)

I stopped the upper Pacman Nebula shot (normal mode) after 17 minutes because I saw too much noise in the photo. Then I repeated the photo as a mosaic and present the "final result" at 34 minutes (2040s, almost one pass).


NGC 281, Jan 10, 2024 - original (103 frames = 1030s), Dual Band Filter		NGC 281, Jan 10, 2024 - large (103 frames = 1030s), Dual Band Filter, photo left processed

NGC 281, Jan 10, 2024 - original (204 frames = 2040s), small mosaic, Dual Band Filter		NGC 281, Jan 10, 2024 - large (204 frames = 2040s), small mosaic, Dual Band Filter, photo left processed

Overall, the mosaic image (bottom row) is somewhat darker despite almost double the exposure time. On the other hand, it does not show the noticeable WP noise of the normal image.

Photos with and without Dual Band Filter

IC 1848 (Soul Nebula)


IC 1848, Jan 9, 2024 - original (3260s), mosaic		IC 1848, Jan 9, 2024 - large (3260s), mosaic, photo left processed

IC 1848, Jan 10, 2024 - original (2550s), small mosaic, Dual Band Filter		IC 1848, Jan 10, 2024 - large (2550s), small mosaic, Dual Band Filter, photo left processed

NGC 281 (Pacman Nebula)


NGC 281, Nov 1, 2022 - original (128 frames = 1280 seconds)		NGC 281, Nov 1, 2022 - large (128 frames = 1280 seconds), photo left processed

NGC 281, Jan 10, 2024 - original (204 frames = 2040 seconds), small mosaic, Dual Band Filter		NGC 281, Jan 10, 2024 - large (204 frames = 2040 seconds), small mosaic, Dual Band Filter, photo left processed

NGC 1499 (California Nebula)


NGC 1499, Feb 7, 2023 - original, mosaic, 4160s		NGC 1499, Feb 7, 2023 large, photo left processed

NGC 1499, Jan 10, 2024 - original, mosaic, 3210s, Dual Band Filter		NGC 1499, Jan 10, 2024 - large, mosaic, 3210s, Dual Band Filter, photo left processed

NGC 2024 (Flame Nebula) and B 33 (Horse Head Nebula)


B 33, IC 434, and NGC 2024, Jan 29, 2023 - large (5700 s), mosaic		B 33, IC 434, and NGC 2024, Jan 29, 2023 - large (5700 s), mosaic, photo left processed

NGC 2024 and B 33, Jan 11, 2024 - original (1910 s), mosaic, Dual Band Filter		NGC 2024 and B 33, Jan 29, 2023 - large (1910 s), mosaic, Dual Band Filter, photo left processed

NGC 7000


NGC 7000 and IC 5070, Nov 10, 2022 - original (721 frames = 7210 seconds), mosaic		NGC 7000 and IC 5070, Nov 10, 2022 - large (721 frames = 7210 seconds), mosaic, photo left processed

NGC 7000 and IC 5070, Jan 11, 2024 - original (363 frames = 3630s), mosaic, Dual Band Filter		NGC 7000 and IC 5070, Jan 11, 2024 - large (363 frames = 3630s), mosaic, Dual Band Filter, photo left processed

First Conclusions

Overall, the images with the Dual Band Filter are convincing for all objects, except that the colors have become somewhat unnatural due to the filter. In addition, the stars are more strongly suppressed, which makes the nebulae stand out more clearly and look more detailed. What you like better, however, may be a different matter...

After all, the Dual Band Filter does not seem to take away much light; sometimes the photos even appear brighter at comparable exposure times.