ngc7000 Ha (Giovanni Fiume)

ngc7000 Ha

Riprese del 7 e 8 luglio, ogni sera 12 frame di 600 secondi.

Stelle distorte ai bordi.

Pensando fosse un problema di backfocus del riduttore/spianatore, nella ripresa del 8 luglio ho accorciato di 0.5mm il backfocus.

Anche in questa ripresa però ci sono stelle ovali.

Esaminando con più attenzione mi sono accorto che questa distorsione non è simmetrica ma presente solo su un bordo dell'immagine.

In particolare:

1) Nella ripresa del 7 luglio si vede la distorsione degli angoli in alto a sinistra, in alto a destra, in basso a destra.

Stranamente in basso a sinistra non appare nessun difetto.

2) Nella ripresa del 8 luglio la distorsione si vede solo su una piccola parte del bordo superiore.

Quindi presumo che il 7 luglio ci sia stato un problema di backfocus, mentre l'8 luglio un problema di tilt.

Non ci facciamo mancare niente ....

Elaborazione in Pixinsight ridotta al minimo: DBE, HT, CT, MLT.

Il progetto continua perchè l'immagine finale sarà una SHO.

*****

Shooting on 7 and 8 July, 12x600 seconds per session.

Distorted stars at the edges.

Thinking it was due to a bad reducer / flattener backfocus, on 8 July I shortened backfocus by 0.5mm.

Even so, however, the stars are oval.

Looking more carefully I realized that this distortion is not symmetrical but present only on one edge of the image.

In particular:

In the July 7 shot, the distortion is present on the corners in the upper left, upper right and lower right.

No defect appears in the lower left.

In the July 8 shot, the distortion is present only on a small part of the upper edge.

So I assume that on July 7 there was a backfocus problem, while on July 8 there was a tilt problem.

Minimal Pixinsight processing: DBE, HT, CT, MLT.

To be continued ... because the final image will be a SHO.

Final
Original
B
C

B

Description: Ripresa del 8 luglio

Uploaded: ...

C

Description: Unione delle riprese del 7 e 8 luglio

Uploaded: ...

DSO

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Backyard
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Status	Advanced success
Started	...
Astrometry.net job	3657377
PixInsight job	Y9DFHFS95LE96C8J0V6CEJHS1NWXWORR
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	20h58m42s.72
RA (top/left)	20h52m31s.51
RA (top/right)	20h53m43s.20
RA (bottom/right)	21h04m38s.88
RA (bottom/left)	21h03m57s.45

Dec (center)	+44°09′01″.4
Dec (top/left)	+45°24′11″.5
Dec (top/right)	+42°45′11″.2
Dec (bottom/right)	+42°52′37″.7
Dec (bottom/left)	+45°32′01″.6

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ngc7000 Ha

ngc7000 Ha

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ngc7000 Ha

ngc7000 Ha

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