From GalaxyMap:This nebula associated with the
Vul OB1 association consists of three regions - star formation began in a diffuse large nebula Sh 2-88A, then spread to the compact HII region Sh 2-88B1, ionised by an O8.5-9.5 V star, and then finally spread to the ultracompact Sh 2-88B2, ionised by a star dimmer than B0.5 V.
Avedisova lists three ionising stars: the O7 V star
HD 338916, the O8.5 Ib supergiant
HD 338926, and the B0.5 V star
LS II +25 09.
From Wikipedia:Sharpless 2-88 or
Sh 2-88 is a region including the [url=mw-redirect=https://en.wikipedia.org/wiki/Diffuse_nebula]diffuse nebula[/url] Sh 2-88A and the two compact
knots Sh 2-88B1 and Sh 2-88B2, all of which are associated with
Vulpecula OB1.Sh 2-88A is an
HII-type diffuse nebula excited by the type
O8 star BD+25°3952.=reference
[4] Both neutral and ionized gases in Sh 2-88 are between 150 and 410
solar masses and the dust mass is about 2 to 9 solar masses. The structure been interacting with a HI interstellar bubble shaped by the stellar winds of BD+25°3952 and the blue O8.5II(f) star BD +25°3866. Overall, its actual structure is located 2.4
kiloparsecs away, at 23 × 15 parsecs in radius. It has a dynamical age of 1.5 million years, and a mass of 1,300 solar masses. It has an
rms electron density of 9 cm−3. All separate star forming regions are 1
arcminute in diameter.=reference
[5]Sharpless 2-88 is the first part of this nebula to have created a star-forming region. It had star formation first start in this large diffuse nebula, which then spread to the other star-forming regions in the nebula.
It spread to the compact Sharpless 2-88B1, then to the ultracompact Sharpless 2-88B2.
Sharpless 2-88B1 is a HII region ionized by an O8.5-9.5 V star, and is compact. It is also associated with a nearby star cluster that contains several massive stars.Sharpless 2-88B2 is a HII region ionized by a star that is dimmer than B0.5 V, and is ultracompact.=reference
[6]I think the two bright areas in the lower left are the two star formation areas (B1 and B2) noted above. Think they are labeled 88A and 88B in the photo.
Previous version shows a lot more stars... I toned them down in this version:
Sh2 88 H-alpha RGB 
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